Sugarloaf — Portugal's tall, soft-centred pão de ló sponge

i. Origin & history

Pão de ló belongs to the great Portuguese tradition of doçaria conventual — the convent sweets built on egg yolks and sugar. For centuries Portuguese convents had eggs in abundance (whites were used to starch linen and clarify wine, the story goes) and access to sugar from Madeira and later Brazil, and they turned the surplus yolks into a whole repertoire of sweets. A light egg-foam cake baked in a clay mould fits squarely into that world, and versions of it are recorded in Portugal from at least the early modern period.

The name is not a literal translation of 'sugarloaf'. Pão means bread or loaf; ló is usually explained as an old word for a fine, light fabric such as gauze, a reference to the cake's airy crumb — though, like many food etymologies, this is a traditional explanation rather than a settled fact. In English the cake is variously called Portuguese sponge cake, pão de ló or, loosely, sugarloaf cake for its tall, domed shape.

Every region of Portugal has an opinion about how it should be made. Pão de ló de Ovar, from the coastal town south of Porto, is the most famous: rich in yolks, baked in an unglazed clay pot lined with paper, and left so soft in the middle that it oozes when cut. It holds protected geographical status. Pão de ló de Alfeizerão, near Alcobaça, is even wetter, its centre essentially a sweet egg cream. Pão de ló de Margaride, from Felgueiras, is the opposite: a firm, fully baked, golden cake that keeps for days.

The cake is above all an Easter food. In much of Portugal godparents traditionally give their godchildren a pão de ló at Easter, and bakeries in Ovar and Alfeizerão produce it in huge numbers in the weeks before. It also travelled: in Brazil pão de ló is the everyday word for a plain sponge, and Japan's sponge-cake culture traces part of its ancestry to castella, a cake introduced by Portuguese traders in the sixteenth century.

ii. Why the centre is meant to be underdone

Pão de ló has no butter, no baking powder and very little flour. Everything that holds it up is egg: whisking eggs with sugar traps millions of tiny air bubbles, and the sugar dissolves into the egg's water and stabilises the foam so it does not collapse. In the oven, the air expands and the egg proteins set around it, fixing the structure in place. The flour is there only to add a little body — much more and the cake turns bready.

The Ovar and Alfeizerão styles use a high proportion of yolks to whites. Yolks are richer and set at a lower temperature into something closer to custard than sponge, so a yolk-heavy batter baked hot and briefly gives a firm, risen outer shell around a centre that has thickened but not fully set. That centre is the point. It is not raw in the sense of a failed cake: the eggs have been heated well past the point of thickening, and the texture is closer to a soft-set crème anglaise.

Heat is the second lever. A fairly hot oven, around 200 °C, sets the outside quickly and gives the cake its rise and its thin, tender crust before the middle has time to dry out. A slower oven would cook the cake evenly through and produce the firmer Margaride style — perfectly good, but a different cake.

The paper lining matters more than it seems. Traditionally the mould is lined with a large sheet of greaseproof paper that stands well above the rim, and the cake is served still wrapped in it. The paper supports the soft sides as the cake rises and cools, and it keeps the wet centre contained when the cake is sliced. Cakes baked in greased, unlined tins tend to sink at the edges and stick.

Finally, the whisking cannot be rushed. The eggs and sugar need eight to twelve minutes in a stand mixer to reach the thick, pale ribbon stage, and the flour must be folded in with the fewest possible strokes. Every unnecessary stir knocks out air the cake will never get back.

iii. Ingredients

Makes 10 servings · scroll the side panel to adjust

• 10 egg yolks, at room temperature
• 3 whole eggs, at room temperature
• 200 g caster sugar
• 80 g plain flour, sifted twice
• 1 pinch of fine salt
• 1 lemon, finely zested (optional)

This is a soft-centred, Ovar-style proportion. Yolks plus a few whole eggs give the richness and custardy middle while the whites in the whole eggs still provide enough lift; for a firmer Margaride-style cake, use 6 whole eggs, 180 g sugar and 120 g flour and bake it through. Room-temperature eggs whip to far greater volume than cold ones. Use caster sugar, which dissolves into the foam; granulated sugar can leave a gritty, weeping crust. Plain flour is traditional — do not use self-raising, as baking powder makes the soft centre collapse into a gummy layer. Lemon zest is a common modern addition but many purists leave the cake unflavoured so the egg tastes of itself. Save the leftover whites for meringues or a hazelnut meringue.

iv. Method

1. Heat the oven to 200 °C (400 °F), conventional rather than fan if you can. Line a 22 cm round tin, at least 7 cm deep, with a single large sheet of greaseproof paper pressed into the base and sides and standing 5 cm above the rim; crumple the paper first so it moulds to the tin.
2. Put the yolks, whole eggs, sugar and salt in the bowl of a stand mixer. Whisk on high speed for 10–12 minutes, until the mixture has roughly tripled in volume, is very pale and thick, and a trail drizzled from the whisk sits on the surface for several seconds before sinking.
3. Add the lemon zest if using. Sift the flour over the foam in two additions, folding each in with a large spatula using a figure-of-eight motion and turning the bowl. Stop as soon as no dry flour is visible.
4. Pour the batter gently into the lined tin from a low height. Do not tap the tin or smooth the surface hard.
5. Bake for 18–22 minutes, without opening the door for the first 15. The cake is ready when it is well risen and deep golden, the top springs back at the edges, and the centre still trembles distinctly when the tin is nudged. For a fully baked cake, give it a further 8–10 minutes until a skewer comes out clean.
6. Let the cake cool in the tin for 20 minutes; the dome will settle slightly and the centre will firm a little. Lift it out by the paper and leave it to cool completely, still wrapped.
7. Serve at room temperature, peeling the paper back and cutting with a sharp knife so the soft centre runs only slightly onto the plate.

v. Tips & common mistakes

• Whisk longer than you think. Under-whipped eggs are the main reason pão de ló comes out flat and dense. The foam should be thick enough to hold a ribbon for several seconds; at that point the bubbles are small and stable enough to survive folding and baking.
• Fold, never stir. The flour is a small quantity in a large volume of foam, so it is tempting to beat it in. A few slow, deep folds are enough; a few streaks are better than a deflated batter.
• Do not open the oven early. A sudden drop in temperature before the outer crust has set makes the dome collapse into the soft centre, and the cake will not recover.
• Judge by wobble, not by skewer. For the soft-centred style a skewer will always come out wet, so use the jiggle in the middle and the springy edges as your cue. Underbaking the edges as well as the centre gives a cake that slumps when unmoulded.
• Keep the paper on. It is not just presentation: the cake's sides are delicate, and the paper is what lets you lift, carry and slice it without it falling apart.
• Use the freshest eggs available. With no butter or flavourings to hide behind, the flavour is almost entirely egg, and fresher eggs also whip into a more stable foam.

vi. Variations

Pão de ló de Ovar is the yolk-rich, soft-centred cake from the Aveiro district, traditionally baked in unglazed clay. Pão de ló de Alfeizerão is wetter still, almost spooned rather than sliced. Pão de ló de Margaride is firm, tall and fully baked, the version that keeps and travels. Pão de ló de Arouca and many convent variants sit in between. In Brazil, pão de ló is the base sponge for layered birthday cakes, and in Spain the comparable cake is the plain bizcocho.

The family resemblance runs wide. France's gâteau de Savoie is another fat-free egg-foam cake, lighter and fully baked; Spain's queen cake uses butter for a closer crumb; and Portugal's own arroz doce and rabanadas share the same egg-and-sugar convent heritage. The yolk-based richness of the soft centre has a cousin in the Brazilian quindim.

vii. Serving & storage

Pão de ló is eaten plain, in thick wedges, at room temperature — it needs no icing, cream or fruit, though a glass of port or Moscatel de Setúbal is a classic pairing at Easter. Firmer versions are good with coffee at breakfast or toasted lightly, and stale slices make an excellent base for trifles and tipsy cakes.

Keep it wrapped in its paper, under a cake cover, at room temperature. The soft-centred style is best within 24 hours and keeps for 2 days; refrigerating it firms the centre and dulls the flavour, so bring it back to room temperature before serving if you must chill it. A fully baked Margaride-style cake keeps for 4–5 days airtight. The firm style freezes well for up to a month, wrapped tightly; the soft-centred version does not, as the custardy middle turns watery when thawed.

ix. More from Spanish & Portuguese

• Arroz Doce — Portuguese rice pudding
• Torrija — Spanish Easter French toast
• Queen Cake — Spanish pound cake
• Gâteau de Savoie — French egg-foam sponge
• Quindim — Brazilian yolk-and-coconut custard
• Matcha Roll Cake — Japanese sponge roll