Italian Penne with Basil Pesto, Roasted Potatoes and Crisp Green Beans | Penne con Pesto di Basilico, Patate Arrosto e Fagiolini Croccanti
Potatoes and green beans belong in a plate of pesto. That has never been in question in Genoa. What is open to argument is how they get there. The old method drops both into the pasta water alongside the noodles, which is efficient and gives a soft, faintly cloudy plate. This version takes them out of the water: the potatoes are roasted until their edges caramelize, the beans are blanched and plunged into ice, and both arrive with a texture boiling cannot give them.
The pasta is penne, an outsider here. Liguria makes trenette and hand rolled trofie, both designed to be coated on the outside. A penna works the opposite way: it is a hollow reservoir with a diagonal opening, and a loose pesto runs into that hollow and waits for the second bite. The shape turns the sauce from a coating into a filling, which is why the pesto here is slacker than one made for trofie.
Nothing in the sauce is cooked. The pesto is pounded raw, thinned with pasta water allowed to cool, and folded through off the heat. Basil is fragile: the compounds that make it smell like basil leave within seconds of a hot pan, and what remains tastes of hay. Every temperature instruction below protects that one thing.
Yield: 4 servings. Prep: 30 minutes. Roast: 35 minutes. Cook: 15 minutes. Total: about 1 hour 20 minutes. Difficulty: easy to intermediate. Course: primo. Region: Liguria, with a Campanian pasta shape.
The Story
Pesto left Liguria in a suitcase. The first written recipe anyone can point to is in La Cuciniera Genovese, published by Giovanni Battista Ratto in 1863, and by then the sauce was old in the city and unknown outside it. What carried it across Italy and then the Atlantic was emigration. Ligurians left the port in huge numbers between 1870 and 1930, taking a sauce that needed no cooking, no oven and no fresh meat, only a mortar and whatever basil grew on a windowsill.
The pasta shape followed a different road. The patent for the diagonal cutting blade was filed in 1865, and Gragnano was already drying pasta in the sea wind on a commercial scale. By the mid twentieth century penne sat on every shelf in Italy and trofie on almost none outside Liguria. A generation met pesto on penne, and Ligurian purists have complained ever since.
The roasted potato has no tradition behind it and is an honest modern correction. In the classic dish the potato boils with the pasta and breaks down at the edges, which costs you the potato as a distinct thing to eat. Roasting it separately gives a browned, sweet, intact cube, and a longer reserve of pasta water makes up the lost starch.
Ingredients
For the pesto
Fresh basil leaves, small and young, 3 oz (85 g), about 4 packed cups
Pine nuts, 1/4 cup (35 g)
Garlic clove, young, germ removed, 1
Parmigiano Reggiano, grated, 1/2 cup (45 g)
Pecorino Fiore Sardo, grated, 1/4 cup (25 g)
Extra virgin olive oil, mild and Ligurian if possible, 2/3 cup (160 ml)
Coarse sea salt, 1/2 tsp (3 g)
For the vegetables
Waxy potatoes, Yukon Gold or similar, 12 oz (340 g)
Green beans, thin and firm, 7 oz (200 g)
Extra virgin olive oil, 2 tbsp (30 ml)
Fine sea salt, 1/2 tsp (3 g)
Freshly ground black pepper, to taste
For the pasta
Penne rigate, bronze die, 14 oz (400 g)
Water for boiling, 5 qt (4.7 l)
Coarse sea salt, 1 1/2 tbsp (28 g)
For finishing
Reserved pasta water, about 3/4 cup (180 ml)
Parmigiano Reggiano, grated, 2 tbsp (10 g)
Pine nuts, toasted, 1 tbsp (9 g)
Small basil leaves, 8 to 12
Extra virgin olive oil, a few drops per bowl
Preparation
Step 1
Roast the potatoes first, because they take the longest. Heat the oven to 425°F (220°C). Peel the potatoes and cut them into cubes of about 3/4 inch (2 cm), large enough to keep a soft centre and small enough to brown all over. Rinse off the surface starch, dry them completely, then toss with 2 tablespoons of olive oil and a quarter teaspoon of fine salt. Spread them on a tray in one layer with space between them and roast 30 to 35 minutes, turning once.
Step 2
Blanch and shock the green beans. Top them but leave the tails on. Bring a small pan of well salted water to a rolling boil and cook them 3 minutes for thin beans, 4 for thicker ones. Bite one: the squeak gone, the snap still there. Move them into water and ice for 2 minutes, then drain and dry them thoroughly. The ice bath is not optional. It stops the cooking and locks in the green.
Step 3
Chill everything that touches the basil. Put the mortar, or the blender jar and blade, in the freezer for 15 minutes. Basil bruises brown because an enzyme in the leaf oxidizes the moment the cell walls break, and that reaction slows sharply as the temperature drops. Wash the leaves only if they need it and dry them completely. Water clinging to the leaves thins the pesto and makes it separate.
Step 4
Pound or blend the pesto. In a mortar, crush the garlic and coarse salt to a paste, add the pine nuts and work them smooth, then add the basil in three handfuls, grinding against the wall in a circle rather than pounding down. Work in both cheeses, then trickle in the oil while stirring. With a blender, pulse in bursts of 3 seconds with the jar cold, scraping down, and add the oil last. Never let it run long enough to warm the sauce.
Step 5
Taste and correct the pesto now, not later. It should be strongly basil forward, salty from the two cheeses and only faintly sharp with garlic. If the garlic dominates, the clove was old, and the only cure is a second batch with less. If it tastes flat, add salt rather than cheese. Cover the surface with a film of olive oil and hold it at cool room temperature, never in the refrigerator, which dulls the aroma within an hour.
Step 6
Cook the penne. Bring the water to a hard rolling boil and add the coarse salt. Drop in the penne, stir for 30 seconds, and cook 1 minute short of the packet time, a smaller margin than a cooked sauce needs because nothing here finishes the pasta over heat. Before draining, reserve a full 1 1/2 cups (360 ml) of the water and set half in a bowl to fall to around 120°F (50°C). That is what loosens the pesto.
Step 7
Loosen the pesto off the heat. Spoon the pesto into a wide bowl and whisk in the cooled pasta water a tablespoon at a time until it flows like thick cream. This step decides the dish. Boiling water straight from the pot scalds the basil and turns the sauce khaki within a minute, and once it goes there it never comes back.
Step 8
Bring it all together. Tip the drained penne into the loosened pesto, add the roasted potatoes and the beans cut into 1 1/2 inch (4 cm) lengths, and fold gently with a rubber spatula rather than tossing over heat. Keep folding about 30 seconds so the sauce works into the hollow of each tube. Loosen with more water if it tightens, season with black pepper and serve at once.
Plating
Warm the bowls only slightly, to around 120°F (50°C), and no more. Every other pasta wants a hot bowl and this one does not: a bowl from a warming drawer keeps cooking the basil from underneath, and the plate is dull by the time it reaches the table. Otherwise use room temperature bowls.
Build with deliberation rather than dumping the pan. Lift the penne into a low mound, then set the best roasted potato cubes and the brightest bean lengths on and around it where they are visible. Buried under the tubes they vanish. Finish with toasted pine nuts, a little grated Parmigiano, basil leaves and a thread of olive oil.
Professional Technique
The defining technique is thermal restraint, unusual in Italian pasta cookery because almost every other sauce is improved by heat. Basil holds its aroma in volatile compounds, principally linalool, eugenol and estragole, all heat sensitive and readily oxidized. Above roughly 140°F (60°C) they leave fast, and the polyphenol oxidase in the leaf browns the chlorophyll at the same time. Cooling the water and folding off the heat keeps everything below that line.
The second is splitting the two vegetables into two cooking methods. Roasting the potato drives off water and browns its surface sugars, giving sweetness and a firm edge boiling cannot. Blanching and shocking the bean sets its colour and halts cooking at a precise point rather than leaving it to soften in residual heat. Cooked together in the pasta water, both end at one texture. Cooked apart, they contribute two.
The third is the mortar itself. Marble and a wooden pestle tear the basil cell walls open by grinding rather than slicing, so the oils are absorbed straight into the nut and cheese paste. A steel blade cuts cleanly, heats the leaf by friction and whips in air, all of which encourage browning.
Texture and Moisture Control
Four textures are in play and none is the sauce: the yielding tube, the crisp edged potato, the snapping bean and the soft pine nut. The pesto is only the medium they travel in, so the risk here is sogginess rather than a broken sauce. Dry the potatoes before the oven and the beans after the ice bath.
Pesto is an emulsion of olive oil held by cheese proteins and crushed nut solids, fragile in both directions. Too little liquid and it clumps into pockets that never reach the inside of the penne. Too much and it slides into a green puddle at the bottom of the bowl. Aim for a sauce that ribbons slowly off a spoon, reserve far more water than you think you need, and add it in small amounts: an overthinned pesto cannot be brought back.
Professional Mise en Place
The vegetables can be done hours ahead, the pesto is best within the hour, and assembly takes two minutes. Order the work that way.
Equipment and tools
Marble mortar and wooden pestle, or a blender jar chilled in the freezer
Heavy sheet tray large enough for the potatoes in one layer
Small blanching pan and a bowl of water and ice beside it
Pasta pot of at least 6 qt and a heatproof bowl for the reserved water
Rubber spatula for folding, not tongs
Prepared ahead
Potatoes roasted and held at room temperature, up to 4 hours ahead
Beans blanched, shocked, dried and cut, up to 8 hours ahead
Cheeses grated and combined, pine nuts toasted and cooled
Garlic peeled and its green germ removed, mortar chilling
Basil picked and dried completely
Service setup
Pesto made, surfaced with oil, held at cool room temperature, never refrigerated
Reserved pasta water resting off the heat to fall to around 120°F (50°C)
Vegetables at room temperature so they do not chill the bowl
Bowls barely warm, garnishes lined up within reach of the pot
Chef Tips
Choose small young basil leaves and reject anything large, dark and leathery. Mature basil develops a minty note that is wrong here, and Ligurian growers pick their plants very young to avoid it. If the only basil available has big leaves, use the top four of each stem and keep the rest for a soup.
Use a mild olive oil, not a peppery one. A powerful Tuscan or Pugliese oil has a bitter green finish that fights the basil for the same part of the palate and usually wins. Ligurian Taggiasca is traditional because it is soft and steps back.
Toast the pine nuts for the garnish but never for the pesto. Raw nuts pound into a creamy paste that binds the emulsion, while toasted ones are drier and resist breaking down. A spoonful of toasted nuts on top gives you both, and the contrast is worth the extra pan.
If you must make the pesto in advance, freeze it rather than refrigerate it, and freeze it without the cheeses, with oil over the surface. Stir the Parmigiano and Pecorino in after thawing. Cheese frozen in the sauce turns grainy, while the basil base freezes well for 3 months.
Common Mistakes
Loosening the pesto with boiling pasta water. This is the most common way the dish is ruined. Water straight off the boil cooks the basil on contact, the sauce turns the colour of old moss and the aroma is gone in under a minute. Let the reserved water sit off the heat to around 120°F (50°C).
Boiling the potatoes with the pasta out of habit. It is the traditional method and it is fine, but it is not this recipe. The design depends on a browned, dry edged cube, and a boiled potato contributes softness and cloudiness instead.
Crowding the roasting tray. Potatoes packed together steam in their own moisture and come out pale and slack rather than crusted. Give every cube a clear border of hot metal, and use two trays if you have to.
Skipping the ice bath for the beans. Beans left to drain hot keep cooking from residual heat, go olive drab and lose the snap the plate is built around. Two minutes in water and ice fixes colour and texture permanently.
Tossing the finished dish over the flame. Pesto is not a pan sauce and gains nothing from heat. Fold it through the pasta with a spatula, off the burner, and if it needs loosening add water rather than returning it to the stove.
Wine Pairing
Gavi DOCG: Cortese grown just north of the Ligurian border, and for centuries the white that travelled down the road into Genoa. It is precise, lightly citrus and distinctly mineral, with a lemon and green apple acidity that lifts the fat of a sauce carrying two thirds of a cup of olive oil. It has almost no aromatic personality of its own, which here is a virtue: the basil needs the space.
Ribolla Gialla Collio DOC: From the far northeast, and a more textural choice. Ribolla Gialla brings a faintly waxy herbal weight and a chalky grip that reads almost like tannin in a white, and that grip answers the roasted potato and the pine nut rather than the basil. Its acidity is bright but restrained, so it does not slice through the pesto emulsion.
Verdicchio di Matelica DOC: The inland, higher and leaner face of Verdicchio, from a valley running against the coast rather than along it. It is firmer and more savoury than its coastal cousin and finishes on a bitter almond note that sits comfortably beside the Fiore Sardo in the pesto. That saline close also suits well seasoned green beans.
Bianco di Custoza DOC: A blend from the moraine hills south of Lake Garda, built on Garganega and Trebbiano with Cortese and Friulano alongside. It has a gently floral top note and a soft rounded middle that suits a warm rather than hot dish, and it is the friendliest bottle here.
Franciacorta DOCG: A metodo classico sparkler with a green sauce is a genuinely good idea. The fine persistent mousse scrubs olive oil off the palate between bites, and the bread and hazelnut notes from lees ageing echo the pine nuts directly. Choose a Brut rather than a Satèn: the higher pressure and drier finish do more work against the fat.
Storage & Reheating
The finished dish does not keep and no technique makes it keep. Dressed pesto pasta left overnight goes dark, the oil separates and the potatoes soften into the sauce. Eat it the day it is made and store only the parts. Roasted potatoes keep 3 days covered in the refrigerator, and blanched beans the same, dried and bagged with a sheet of paper towel to absorb condensation.
Pesto keeps 4 days refrigerated in a small jar with a finger of olive oil sealing the surface, and the jar should be as full as possible, since oxygen rather than time darkens it. For longer storage freeze it without the cheeses for 3 months, in an ice cube tray.
Do not reheat dressed leftovers in a pan or a microwave. Let the portion come to room temperature for 30 minutes, then loosen it with a tablespoon of warm water and a fresh teaspoon of pesto stirred through cold. Refresh the potatoes in a hot oven for 5 minutes if you want their edge back.
Nutrition
Per serving, based on 4 portions:
Calories: 830 kcal
Total Fat: 47 g
Saturated Fat: 9 g
Trans Fat: 0 g
Unsaturated Fat: 36 g
Cholesterol: 20 mg
Sodium: 720 mg
Total Carbohydrates: 85 g
Fiber: 7 g
Total Sugars: 5 g
Added Sugars: 0 g
Protein: 22 g
Lactose: 0.4 g
Principal micronutrients: vitamin K, vitamin C, calcium, magnesium, manganese, folate, vitamin E
These are estimates. Most of the salt in the pasta water is discarded rather than eaten, and the fat total is dominated by the olive oil in the pesto, which is largely monounsaturated.
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