Italian Piedmontese Onion Frittata | Frittata di Cipolle alla Piemontese
A thick frittata of slowly stewed Piedmontese onions, eight eggs and finely grated Grana Padano, started in butter, set on the stove and finished in the oven, then turned out onto a board to rest before it is cut. It is served warm on the day and cold the day after, which in Piedmont is the more usual.
The technical weight of the recipe does not sit where people expect. The onions need time, low heat and a dry pan. The eggs decide the dish, and three decisions are taken before they touch heat: how much they are beaten, when they are salted, and how cold the onions are. Get those wrong and no attention at the stove will recover it.
Yield: 4 main course servings or 6 as an antipasto. Prep: 20 minutes. Cook: 55 minutes. Rest: 15 minutes for the onions plus 5 for the frittata. Total: about 1 hour 35 minutes. Difficulty: intermediate. Course: secondo or antipasto. Region: Piedmont, the Novara plain and the hills east of Turin.
The Story
Piedmont eats frittata cold, and that habit explains the dish. The merenda sinoira, the long late afternoon table of the Langhe and the Monferrato that sits between lunch and supper, is built of cold things: salame, tomini under oil, anchovies in green sauce, peppers, a frittata in wedges. One made for that table is thick, made in the morning and judged the next day, and air pockets, a damp base and rubbery edges all show more cold than hot.
Piedmont also grows onions worth naming. The cipolla bionda di Cureggio e Fontaneto, a flat pale onion from the plain north of Novara, survives as a Slow Food presidium after nearly disappearing; the cipolla di Andezeno, in the hills east of Turin, still has its own summer sagra. These are sweet, thin skinned, water heavy onions grown as a field crop, and a frittata was one way a household worked through a sack of them.
The rest is the cooking of the cascina: eggs from the yard, onions from the row outside the door, grated cheese from whichever wheel was open, which between Novara and Alessandria meant Grana Padano. The regional fat is butter rather than olive oil, because this is the Italy of Alpine dairy. It was food for the field, cut cold and wrapped in paper with bread.
Ingredients
For the onions
Sweet yellow onions, cipolla bionda di Cureggio e Fontaneto or cipolla di Andezeno, 1 3/4 lb (800 g)
Unsalted butter, 2 tbsp (28 g)
Extra virgin olive oil, 1 tbsp (15 ml)
Fine sea salt, 1/2 tsp (3 g)
Dry white wine, 1/4 cup (60 ml)
Bay leaf, 1
Freshly ground black pepper, to taste
For the egg mixture
Large eggs, 8
Grana Padano DOP, finely grated, 2 1/2 oz (70 g)
Fine sea salt, 3/4 tsp (4.5 g)
Flat leaf parsley, finely chopped, 1 tbsp (4 g)
Freshly ground black pepper, to taste
For cooking and finishing
Unsalted butter, 1 tbsp (14 g)
Extra virgin olive oil, 1 tbsp (15 ml)
Toma Piemontese DOP, shaved thin, 1 oz (30 g), optional
Coarse salt flakes, a small pinch
Preparation
Slice the onions
Peel the onions, halve them through the root and cut each half into half moons a scant 1/8 inch (3 mm) thick. Evenness matters more than fineness: thick pieces stay firm while thin ones dissolve. Use a knife, not a mandoline, which crushes a sweet thin skinned onion. You will have about 6 cups, which looks like too much and is not.
Sweat the onions covered
Melt the 2 tbsp (28 g) of butter with the tablespoon of oil in a wide saute pan over low heat. Add the onions, the bay leaf and 1/2 tsp (3 g) of salt, stir once and cover. Cook 30 minutes, stirring every 8 to 10 minutes. Nothing should colour, and frying noise means the heat is too high.
Deglaze and dry the pan
Uncover, raise the heat to medium and add the 1/4 cup (60 ml) of white wine. Cook uncovered 10 to 15 minutes, stirring often, until the pan is dry and the onions crush against the spoon, pale gold at most. Drag the spoon across the base: if liquid runs back into the track, keep going, because whatever is left ends up inside the set egg. Discard the bay leaf.
Cool the onions completely
Spread them in a thin layer on a cold plate for 15 minutes, or 10 in the refrigerator. A thin layer loses heat in a fraction of the time a heaped bowl needs, and they must feel properly cool to a fingertip before they meet the eggs.
Salt the eggs and let them rest
Break the 8 eggs into a bowl, add the 3/4 tsp (4.5 g) of salt and mix with a fork only until the yolks break and the mixture runs one even yellow, about 20 seconds. Leave the bowl on the counter 10 minutes. It will loosen visibly and show no foam, and that loosening is the salt at work.
Combine cheese, parsley and onions
Heat the oven to 350°F (175°C). Fold the grated Grana Padano into the eggs with a spatula, with the parsley and a grind of pepper, then fold in the cooled onions in three additions, turning rather than stirring. Ten or twelve passes, and do not beat again.
Set the base on the stove
Put a 10 inch (25 cm) nonstick ovenproof pan over medium low heat with the 1 tbsp (14 g) of butter and the tablespoon of oil. When the butter stops foaming, pour in the mixture and level it. Leave it alone 6 to 8 minutes, until the edges set and pull away slightly while the centre is still liquid. Lift an edge: pale gold, no more.
Finish in the oven, turn out and rest
Move the pan to the oven for 10 to 14 minutes, until a thermometer in the middle shows 158 to 160°F (70 to 71°C) and the centre still feels soft under a fingertip. Run a spatula round the edge and underneath and turn it out onto a wooden board, uncovered, for 5 minutes: carryover brings it to about 165°F (74°C).
Plating
Cut and serve it from the board, not the pan, each wedge in a single stroke rather than sawing, which drags the crumb: four wedges for a main course, six for an antipasto. Plates go to the table at room temperature, since a warmed plate keeps cooking the underside and softens the base.
What goes beside it stays plain. A spoonful of bagnet verd, the Piedmontese sauce of parsley, anchovy, garlic and vinegar soaked breadcrumb, set next to the wedge and never spooned over it. A few thin shavings of Toma on the warm surface so they slump without melting, a pinch of salt flakes, grissini, a sharp green salad. For the cold service, let the frittata come to room temperature over 30 minutes, cut it thinner since it is firmer, and serve it with salame and pickled peppers.
Professional Technique
Everything technical in this frittata is the beating of the eggs. Whisking drags air into the mixture, and egg white protein is extremely good at wrapping itself around a bubble and holding it there, which is why it makes meringue. A whisked mixture is a foam whether it looks like one or not. In the pan those bubbles expand as the gas warms, the frittata visibly rises, and the protein sets into walls around the cavities. Off the heat the gas contracts, and with no starch or gluten to hold the lift the structure falls. What reaches the table puffed and then collapsed: an open crumb full of large irregular holes and a rubbery bite, the protein stretched thin around air instead of set as a compact curd. So the eggs are mixed with a fork, the time it takes to break the yolks and no more.
When the salt goes in is the least known of the three decisions. Salt does not need heat to work on egg protein: chloride ions shield the charges that hold each protein folded on itself, and the strands begin to unfold in the cold bowl. Because part of that unfolding is already done by the time the mixture reaches the pan, the proteins need fewer bonds with one another to set, and the network they build is looser and holds more water. The result is a measurably more tender frittata from identical ingredients, and it needs ten minutes at room temperature. Salt added as the mixture hits the pan seasons it and nothing else.
The grated cheese is doing structural work and not only flavouring. It brings fat and its own casein into the mixture, and both get physically in between the egg proteins as they coagulate. Solid fat particles interrupt the network so the strands cannot draw together as tightly, and the contraction that squeezes water out of overcooked egg is reduced. That is why the cheese is grated fine and folded through rather than scattered on top, where it does nothing for the interior. About 2 1/2 oz (70 g) to eight eggs seasons and protects; double that gives a dense interior.
The last decision is temperature rather than cooking. Piedmontese onions straight from the pan sit far above the temperature at which egg protein begins to coagulate, and tipping them into the eggs sets the egg they touch instantly and only where they touch it. Those points become small firm pale lumps that never smooth out and show as specks on a cut face. Worse, that local setting happens before the salt and the cheese have had any effect, so the parts that set first get none of the protection. Cook the onions, cool them, and test with a fingertip before they go in.
Texture and Moisture Control
Judge this frittata on the cut face. You want a close grained interior, uniform and faintly glossy, tender enough to give under a fork and firm enough to hold a wedge upright. Each fault writes itself there. Large irregular holes mean air was beaten in, a dry crumbly interior with a grey cast means too long in the oven, and a pale damp seam above the base means liquid that should have left the onion pan. Pull it at 158 to 160°F (70 to 71°C) at the centre, because one that looks perfect in the pan is overdone on the board.
Butter is the Piedmontese fat and behaves nothing like oil. It is roughly a sixth water and carries milk solids that brown well below the point where oil would smoke, so the base colours sooner than you expect; an equal amount of olive oil alongside raises the temperature at which those solids scorch. Hold the heat at medium low, pale gold underneath and never brown, since chasing colour tightens the layer against the metal into a skin that turns leathery overnight. Turn it out onto a board or a rack, never a plate, where escaping steam condenses into a film of water underneath. Serve it warm rather than hot, around 100 to 110°F (38 to 43°C).
Professional Mise en Place
The onions take 45 minutes and can be done two days ahead. The eggs take 30 seconds and cannot be done ahead at all.
Equipment and tools
10 inch (25 cm) nonstick ovenproof pan, straight sided
Wide saute pan with a lid
Instant read thermometer
Fine grater, flexible spatula, table fork
Wooden board for turning out and resting, never a plate
Prepared ahead
Onions stewed, dried and refrigerated, up to 2 days
Grana Padano grated, up to 1 day, covered and cold
Parsley chopped on the day, not before
Eggs out of the refrigerator 30 minutes ahead
Oven at 350°F (175°C) before the eggs are salted
Service setup
Eggs salted and resting, timer on 10 minutes
Onions spread thin and cool, fingertip tested
Pan on medium low with butter and oil, thermometer to hand
Board and spatula ready for the turn out
Plates at room temperature, bagnet verd and Toma portioned
Chef Tips
Buy the sweetest onions you can find, and firm. A sprouting or soft shouldered onion carries a sharp note that 45 minutes of stewing will not remove. Keep the pan wide, since onions heaped deep steam instead of stewing.
Let the pan size set the depth. A 10 inch (25 cm) pan puts this quantity a little under an inch deep. In an 8 inch pan the same mixture is half again as deep, so drop the oven to 325°F (165°C) and add 5 minutes.
Mix the eggs in a clear glass bowl. Foam is nearly invisible from above in a metal bowl and obvious from the side in glass, and seeing it stops you reaching for a whisk out of reflex.
Cook the onions the day before whenever you can. They lose nothing overnight and the cooling problem solves itself while you sleep, which removes the step people rush. Take them out with the eggs so they are cool, not cold.
Common Mistakes
Whisking the eggs instead of mixing them. The mixture becomes a foam, the frittata rises and collapses as it cools, and the crumb is left open and rubbery. Use a fork and stop when the colour is even.
Folding in the onions while they are still hot. They coagulate the egg wherever they touch it, leaving firm pale lumps that never blend back in. Spread them thin on a cold plate for a full 15 minutes.
Salting the eggs as the mixture goes into the pan. Salt needs ten minutes in the cold mixture to unfold the proteins and give a tender set. Added at the last second it seasons the frittata and nothing more.
Raising the heat to get colour on the base. The egg against the metal tightens into a tough skin while the centre is still liquid, and that skin turns leathery by the next day. Stay at medium low and let the oven finish it.
Adding milk, cream or flour to the eggs. Milk and cream introduce water that leaves as a damp seam under the surface, and flour makes the interior pasty. It needs no help holding together.
Wine Pairing
Erbaluce di Caluso DOCG: The local answer, grown on the glacial moraine hills north of Turin an hour from where these onions are pulled. Very high acidity, modest alcohol, green apple and a stony finish, and acidity is what egg yolk needs, since yolk fat coats the palate and stays there. No oak and no residual sugar to get in the way of the cheese.
Roero Arneis DOCG: From the sandy left bank of the Tanaro, across the river from Barbaresco. Arneis has less acidity than Erbaluce and more body, with pear, white flowers and a faintly bitter almond finish, and that extra weight suits the butter in the pan better than a leaner white. The bitter note at the end runs alongside the Grana Padano. Serve it at 50°F (10°C) and no colder.
Gavi DOCG: Cortese from the hills of southeastern Piedmont near the Ligurian border, lean, saline and citric with almost no fruit sweetness. Pour it when the frittata is eaten cold, because chilled egg fat sits firmer on the palate and takes more cutting than a warm wedge. It refreshes between mouthfuls rather than commenting on the dish.
Barbera d'Asti DOCG: The Monferrato bottle that would genuinely be on the table, and it works for a reason that sounds wrong until you taste it. Barbera has high acidity and very little tannin, close to ideal with egg: the acidity cuts the butter and the yolk while the lack of grip keeps it from clashing with the protein. Choose a young unoaked bottling, not a barrique aged Superiore.
Storage & Reheating
Let the frittata cool completely and uncovered on its board, then wrap it in parchment and keep it whole in the refrigerator for up to 3 days, since every cut face dries. It improves on the second day: the onion flavour distributes and the crumb firms enough to cut thin clean wedges. Do not store it on a plate under cling film pressed against the base.
Do not freeze the finished frittata. Ice crystals rupture the protein network and cooked egg releases its water on thawing, so the wedge comes out spongy and sitting in liquid. The stewed onion base freezes well for up to 2 months, flat in a sealed bag.
If warm is wanted, use a 300°F (150°C) oven for 8 to 10 minutes with the frittata on a rack and uncovered. Single wedges do better in a pan: a scrap of butter over low heat, 2 minutes a side. Never a microwave, which drives the centre past the point where the protein contracts and returns a rubbery wedge in a puddle.
Nutrition
Per serving, based on 4 main course portions:
Calories: 440 kcal
Total Fat: 30 g
Saturated Fat: 12 g
Trans Fat: 0.5 g
Unsaturated Fat: 17 g
Cholesterol: 410 mg
Sodium: 940 mg
Total Carbohydrates: 19 g
Fiber: 3 g
Total Sugars: 8 g
Added Sugars: 0 g
Protein: 21 g
Lactose: less than 0.5 g
Principal micronutrients: choline, vitamin B12, vitamin A, vitamin D, riboflavin, selenium, calcium, phosphorus
These figures are estimates. Sodium comes almost entirely from the salt and the Grana Padano. Cut into 6 antipasto portions instead of 4, everything above falls by a third.
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