Zserbó Szelet — Hungarian walnut, apricot and chocolate slice

i. Origin & history

Zserbó is the Hungarian spelling of Gerbeaud — the name of Émile Gerbeaud, the Swiss confectioner who from 1884 ran the famous patisserie on what is now Vörösmarty Square in Budapest. The layered walnut-and-apricot slice is credited to his house and carries his name, written the way Hungarians pronounce it. The café's own story, and the cake as it is sold there, is told on our Gerbeaud cake page; this page is about the slice as Hungarian households bake it.

Because it travelled out of the café and into home kitchens so thoroughly, zserbó now belongs to the everyday Hungarian baking repertoire rather than to one shop. It is one of the standard items on the Christmas sütemény plate, alongside bejgli (walnut and poppy-seed rolls), linzer biscuits and mézeskalács gingerbread, and it turns up at weddings, name days and Sunday coffee. Every family has a slightly different version, and most of them are written on cards handed down rather than in books.

The flavours are thoroughly Hungarian. Walnuts are the country's great baking nut, used in bejgli, in somlói galuska and in countless cakes; apricot jam — baracklekvár, often made from Kecskemét apricots — is the standard filling and glaze jam of Central European patisserie. Dark chocolate on top marks it as a café-born cake rather than a peasant one.

Spellings vary: zserbó, zserbó szelet, zserbó sütemény, and in English simply Gerbeaud slice or Hungarian layered walnut cake. They are all the same dessert.

ii. What the yeast does in a short pastry

The surprising thing about a traditional home zserbó dough is that many recipes contain a little yeast. It is not a bread dough — there is a great deal of butter, it is not kneaded for long and it is not left to rise to double — but the small amount of fresh or dried yeast, dissolved in warm milk, changes the pastry's character.

A pure shortcrust, baked in thin sheets with wet filling between them, tends to become either crumbly-dry at the edges or pasty where the jam meets it. The yeast adds a faint lift and a softer, more open crumb, so the thin sheets bake into something closer to a tender cake layer than a biscuit. That softness is what lets the slice absorb a little moisture from the jam over a day or two and become uniformly tender rather than soggy in patches. Sour cream does a similar job, adding acidity and fat that keep the crumb short and soft.

The sheets must be thin — about 3 mm. With three pastry layers and two filling layers in a slice only around 3 cm tall, thick pastry overwhelms the filling and the slice eats like a dry biscuit sandwich. Rolling each portion between sheets of baking paper to the exact size of the tin is the cleanest way to manage it, because the rich dough tears easily when lifted.

Finally, zserbó is a cake that needs time. Freshly baked, the layers are distinct and slightly crisp; after resting overnight under a weight, the jam's moisture migrates into the pastry, the layers compress and bond, and the slice cuts cleanly. Cutting it on the day it is baked is the most common reason for crumbly, sliding layers.

iii. Ingredients

Makes 24 servings · scroll the side panel to adjust

• 450 g plain flour
• 250 g unsalted butter, cold
• 60 g icing sugar
• 7 g dried yeast (or 15 g fresh)
• 100 ml warm milk
• 1 egg
• 2 tbsp sour cream
• ¼ tsp salt
• 250 g walnuts, finely ground
• 150 g caster sugar
• 1 lemon, zest only
• 350 g apricot jam
• 150 g dark chocolate (60–70%)
• 40 g unsalted butter (glaze)
• 2 tbsp milk (glaze)

Walnuts should be ground finely but not to a paste; a nut mill or short pulses in a food processor with some of the sugar works. Use a sharp, not-too-sweet apricot jam — its acidity is what cuts through the walnut and chocolate. If it is very firm, warm it so it spreads thinly without tearing the pastry. The yeast can be replaced with 1 tsp baking powder for a slightly shorter, more biscuit-like pastry, which is also common. Sour cream keeps the dough tender; Greek yoghurt is an acceptable stand-in. For the glaze, a good dark chocolate with a little butter gives a soft, sliceable top that will not shatter when cut.

iv. Method

1. Stir the yeast and a pinch of the icing sugar into the warm milk (about 37°C) and leave for 10 minutes until foamy.
2. Rub the cold butter into the flour, remaining icing sugar and salt until it looks like coarse breadcrumbs. Add the yeast mixture, egg and sour cream and bring together into a soft, smooth dough without over-kneading. Divide into three equal pieces, wrap and chill for 30 minutes.
3. Mix the ground walnuts, caster sugar and lemon zest. Line a 25 × 35 cm baking tin with baking paper and heat the oven to 180°C (160°C fan, 350°F).
4. Roll the first piece of dough between two sheets of baking paper to the size of the tin, about 3 mm thick, and lay it in the tin. Prick all over with a fork and bake for 8–10 minutes until just set and pale.
5. Spread half the jam thinly over the part-baked sheet and scatter evenly with half the walnut mixture. Roll out the second sheet, lay it on top and press gently. Repeat with the remaining jam and walnuts, then top with the third sheet. Prick the top all over.
6. Bake for 30–35 minutes until the top is light golden and the edges have shrunk slightly from the tin. Cool completely in the tin.
7. Cover the cooled slice with baking paper and a board with a light weight on top, and leave overnight at cool room temperature.
8. Melt the chocolate, butter and milk together over a pan of barely simmering water, stirring until glossy. Pour over the slice, spread level and leave to set for 1–2 hours. Cut into small squares or diamonds with a hot, dry knife.

v. Tips & common mistakes

• Part-bake the bottom sheet. A few minutes alone in the oven sets the base so jam cannot soak straight through it — otherwise the bottom layer comes out pale and pasty.
• Roll on baking paper, not flour. The dough is rich and soft; extra flour toughens it, and paper lets you flip each thin sheet into the tin in one piece.
• Spread the jam thinly. Thick jam boils at the edges, glues to the tin and makes the slice slide apart when cut. A thin, even film is enough.
• Prick the top layer well. Steam from the filling otherwise lifts the top sheet into bubbles, and the chocolate pools in the dips.
• Rest it overnight under a weight. This is what turns separate layers into a compact slice that cuts cleanly — patience matters more here than any ingredient.
• Glaze only once fully cool. On a warm slice the chocolate soaks in and dulls. Add butter or milk to the chocolate so it sets soft enough to cut without cracking.

vi. Variations

Four-sheet zserbó uses four thinner pastry layers and three fillings for a finer, more café-like slice. Baking-powder zserbó swaps the yeast for baking powder, giving a crisper, shorter pastry. Some families add raisins to the walnut layer, swap in plum jam (szilvalekvár) or raspberry jam for apricot, or replace the chocolate glaze with a cocoa and sugar icing. Gluten-free versions with a nut-flour pastry exist but lose the tender layering.

For the Budapest café version and its story, see Gerbeaud cake. Close cousins in the Central European tradition include the jam-and-nut lattice Linzer torte, the Polish kremówka and the Hungarian poppy-seed bread pudding mákos guba.

vii. Serving & storage

Zserbó is cut small — 4 cm squares or diamonds — because it is rich, and served at room temperature with coffee or tea, or arranged on a mixed Christmas plate with other sütemények. It does not need cream or any accompaniment.

It keeps very well: a week in an airtight tin at cool room temperature, and it improves for the first two or three days as the layers settle. In a warm kitchen, keep it in the fridge but bring it back to room temperature before serving so the pastry softens. Zserbó freezes well for up to two months, unglazed or glazed, wrapped tightly; thaw overnight in the fridge. It is an ideal make-ahead bake for Christmas.

ix. More from Eastern European

• Gerbeaud Cake — the Budapest café original
• Somlói Galuska — Hungarian sponge and rum trifle
• Mákos Guba — Hungarian poppy-seed bread pudding
• Linzer Torte — Austrian nut and jam tart
• Medovik — Russian layered honey cake
• Kremówka — Polish cream slice