Napoleon Cake — the Russian many-layered custard cake

i. Origin & history

The idea of stacking puff pastry with cream is French: the mille-feuille ('thousand leaves') of classic French patisserie, three layers of puff pastry with pastry cream and an iced top, was well established by the nineteenth century. In English-speaking countries it is often called a napoleon. That name probably has nothing to do with the emperor; the commonest explanation is that it is a corruption of napolitain, 'from Naples', a term used in French pastry for layered confections. So when people ask 'Napoleon cake is another name for what dessert?', the answer is the mille-feuille.

In Russia the cake took a different shape and a different story. The best-known legend holds that it was created in 1912 for the centenary of Russia's victory over Napoleon's army, cut into triangles to resemble the emperor's bicorne hat and covered in crumbs to recall the snow of the 1812 retreat. It is a good story and is told everywhere, but there is little hard evidence for it, and the name may simply have come into Russian from the French and English 'napoleon'. Who invented it is not known.

What is certain is its place in Soviet home life. Because it needed no special equipment — just flour, butter, eggs, milk and a baking sheet — and because pre-made puff pastry was rarely available, Soviet cooks developed quick, rough puff doughs and baked the thin layers one by one, trimming them round a plate. Napoleon became the cake for New Year, birthdays and 8 March, made the day before and left to rest in the cold. It remains one of the most-loved cakes in Russia, Ukraine, Belarus, the Baltics, Georgia (as Napoleoni) and across the diaspora.

Its relatives are close: Polish kremówka, also called napoleonka, is a two-layer cream slice; Slovenian kremna rezina adds a whipped-cream layer; and the other Russian layer-cake classic, medovik, uses honey sponge sheets rather than pastry.

ii. Why a crisp pastry is left to go soft

The defining difference between Napoleon and mille-feuille is texture. A French mille-feuille is assembled shortly before serving so the pastry shatters. A Russian Napoleon is designed to soften: many very thin, deeply baked layers are spread with a generous, fairly loose custard cream and left for at least twelve hours. The pastry absorbs moisture from the cream and turns tender and almost cake-like, while the many layers keep a faint flakiness. Cut too soon, it is crunchy, slides apart and leaks cream.

That is why the pastry is usually a quick, rough puff rather than a laminated one. Frozen butter is grated or cut into the flour and bound with an egg, cold water and a spoon of vinegar or vodka. The acid and alcohol both limit gluten development, keeping the dough tender and easy to roll very thin. Pockets of cold butter still create steam and some flaking, which is all the cake needs. The layers are rolled to 2–3 mm and baked hard, deep golden all over: pale pastry turns doughy when it absorbs the cream.

The cream is a zavarnoy krem, a cooked custard thickened with flour or cornflour, often enriched with soft butter once cool. The butter adds body and stops the cream simply soaking away into the pastry, while the custard supplies the moisture to soften it. Too thick a cream and the cake stays dry; too thin and it slides. A custard that just holds soft peaks off the spoon, before the butter, is about right.

iii. Ingredients

Makes 12 servings · scroll the side panel to adjust

• 450 g plain flour, plus extra for rolling
• 250 g unsalted butter, frozen
• 1 egg
• 120 ml ice-cold water
• 1 tbsp vodka or white wine vinegar
• ¼ tsp salt
• 1000 ml whole milk
• 4 eggs (custard)
• 220 g caster sugar
• 70 g plain flour or cornflour (custard)
• 2 tsp vanilla extract
• 150 g unsalted butter, soft (custard)

Use ready-made all-butter puff pastry (about 1 kg) if you prefer; roll it thinner than packaged. For homemade, the butter must be frozen so it can be grated and stays in distinct pieces. Vodka or vinegar keeps the dough tender. In the custard, flour gives the traditional soft, slightly heavier cream; cornflour gives a cleaner, glossier set. Some families replace the butter in the cream with whipped double cream for a lighter, plombir-style filling; it must then be kept chilled.

iv. Method

1. Make the custard first: heat the milk until steaming. Whisk the 4 eggs, sugar and flour in a bowl, then whisk in the hot milk gradually. Return to the pan and cook over medium heat, whisking constantly, until thick and bubbling, about 5–7 minutes. Stir in the vanilla, press cling film onto the surface and cool completely.
2. For the pastry, grate the frozen butter into the flour and salt, tossing to coat. Beat the egg with the water and vodka, add to the flour and bring together quickly into a rough dough. Divide into 8 pieces, wrap and chill for at least 1 hour.
3. Heat the oven to 200°C (180°C fan, 400°F). Roll each piece on a sheet of floured baking paper to a 2–3 mm round slightly larger than 24 cm. Prick all over with a fork.
4. Bake one or two layers at a time for 8–10 minutes until deep golden brown and crisp. While still hot, trim each to a 24 cm circle using a plate as a guide, saving all trimmings.
5. Beat the soft butter until pale, then beat in the cold custard a spoonful at a time to a smooth, creamy filling.
6. Place one pastry round on a board and spread with a thick layer of cream, about 3–4 tablespoons. Repeat with all layers, pressing each lightly, and finish with cream over the top and sides.
7. Crush the trimmings to fine crumbs and press them all over the top and sides.
8. Cover loosely and refrigerate for at least 12 hours, ideally 24, until the pastry has softened and the cake cuts cleanly.

v. Tips & common mistakes

• Bake every layer dark. Pale layers absorb cream into a soggy, doughy cake. They should be golden-brown and snap cleanly.
• Trim while hot. Baked puff pastry shatters once cool; hot it cuts neatly round a plate or cake ring.
• Keep the cream generous. A Napoleon needs enough cream to soften every layer — skimping gives a dry, crunchy cake that crumbles when sliced.
• Butter and custard at similar temperatures. Very cold custard into soft butter can split. Let both sit at cool room temperature and add the custard gradually.
• Roll on baking paper. Very thin dough cannot be lifted; roll it on the paper you bake it on.
• Give it the full rest. Twelve hours minimum. This is a make-ahead cake by nature.

vi. Variations

Napoleon with plombir cream folds whipped cream into the custard for a lighter cake. Condensed-milk cream beats butter with sweetened condensed milk, a common Soviet shortcut. Rectangular Napoleon is built on baking-sheet-sized layers and cut into squares or triangles. Napoleon with berries layers fresh raspberries or cherries into the cream.

Across Europe: French mille-feuille is three crisp layers with a glazed top; Polish kremówka is two layers with thick custard; Austrian Cremeschnitte and Slovenian kremna rezina are cream slices in the same family.

vii. Serving & storage

Serve Napoleon cold from the fridge, cut into wedges or triangles with a long sharp knife, with black tea or coffee. It is the centrepiece cake at New Year and birthdays in many Russian and Ukrainian families, and needs no garnish beyond its crumbs.

Keep it covered in the fridge for up to 4 days; it is best on days one and two. The baked pastry layers can be made several days ahead and kept airtight. The assembled cake freezes reasonably well for up to a month, wrapped tightly, though the cream becomes slightly denser; thaw overnight in the fridge.

ix. More from Eastern European

• Medovik — Russian layered honey cake
• Kremówka — Polish cream slice
• Kremna Rezina — Slovenian cream slice
• Cremeschnitte — Austrian custard slice
• Gerbeaud Cake — Hungarian walnut slice
• Sernik — Polish baked cheesecake