Käsekuchen — German quark cheesecake

i. Origin & history

Cakes made from fresh cheese are among the oldest sweets in Europe. The ancient Greeks and Romans baked cheese with honey and flour, and curd-cheese tarts appear in medieval and early-modern cookbooks across the continent. In the German-speaking lands, where fresh cheese was a staple of farming households, such cakes became part of everyday baking, especially in spring when milk was plentiful and at Easter, when eggs and dairy returned to the table after Lent.

The cheese at the heart of Käsekuchen is Quark, a fresh, unripened curd cheese made by souring milk and straining the whey. It is smooth, spoonable, mildly acidic and, in its classic form, low in fat — a texture somewhere between thick yogurt and ricotta. Germans eat it in huge quantities, at breakfast, in savoury dishes and in baking. In Austria and Bavaria the same cheese is called Topfen, and the cake Topfenkuchen or, in a tart form, Topfentorte.

Käsekuchen is consistently one of Germany's favourite cakes and is found in every bakery and café, usually sold by the slice. It is a cake for afternoon coffee on Sundays, for birthdays and for family gatherings, and every household has its own recipe — with or without a base, with or without raisins, with mandarins or with a streusel topping.

German immigrants carried cheesecake to the United States in the nineteenth century, and it is one of the roots of the American tradition, although American cheesecake took a different path once cream cheese became widely available. The two are now quite different cakes: New York cheesecake is dense, rich and creamy; Käsekuchen is light, moist and tangy, with a texture closer to a soufflé.

ii. What quark does — and how to stop it cracking

Quark is wetter and leaner than cream cheese. That gives Käsekuchen its fresh, tangy taste and soft texture, but it also means the filling needs help to set. A little starch — cornflour, or the vanilla custard powder (Vanillepuddingpulver) that many German recipes call for — binds the extra moisture so the cake slices cleanly. Melted butter and a little cream add the richness that low-fat quark lacks.

Many traditional recipes separate the eggs, beating the whites to soft peaks and folding them in at the end. The trapped air makes the filling rise in the oven like a soufflé, giving an exceptionally light, fluffy texture. The cost is that it also sinks a little as it cools, and that the risen surface is prone to cracking.

Cracks form when the outside of the filling sets and the inside continues to expand, or when the cake contracts too quickly as it cools. German bakers have several remedies: baking at a moderate temperature, around 170 °C; running a knife around the edge of the cake after 10 to 15 minutes in the oven, so the filling can rise freely; and letting the finished cake cool slowly in the switched-off oven with the door ajar.

Quark varies in fat and water content. German quark is sold as Magerquark (low-fat), 20 per cent and 40 per cent fat in dry matter. Lower-fat quark gives a lighter cake but needs more butter or cream; full-fat quark gives a creamier result. Very wet quark should be drained in a sieve lined with muslin for an hour before use.

iii. Ingredients

Makes 12 servings · scroll the side panel to adjust

• 200 g plain flour (base)
• 70 g caster sugar (base)
• 100 g cold unsalted butter (base)
• 1 egg (base)
• 1 pinch salt
• 1 kg quark (20–40% fat), well drained
• 160 g caster sugar (filling)
• 4 eggs, separated
• 40 g vanilla custard powder or cornflour
• 100 g unsalted butter, melted and cooled
• 200 ml double cream or whole milk
• 1 unwaxed lemon, finely grated zest and 1 tbsp juice
• 1 tsp vanilla extract
• 60 g raisins, soaked in rum or water (optional)

Quark is now sold in many supermarkets outside Germany. If you cannot find it, use a mix of strained full-fat Greek yogurt and ricotta, or half fromage frais and half cream cheese; the result will be close but slightly richer. American-style cream cheese alone makes a dense, heavy cake that is no longer Käsekuchen. Vanilla custard powder gives the classic German flavour and colour; cornflour with vanilla extract does the same job. The raisins are traditional but divisive — leave them out if you prefer.

iv. Method

1. For the base, rub the cold butter into the flour, sugar and salt, then add the egg and knead briefly to a smooth dough. Wrap and chill for 30 minutes.
2. Butter a 26 cm springform tin. Roll out the dough and press it over the base and about 4 cm up the sides. Prick the base with a fork and chill while you make the filling.
3. Heat the oven to 170 °C (340 °F), conventional heat.
4. Beat the quark, 120 g of the sugar, the egg yolks, custard powder, melted butter, cream, lemon zest and juice and vanilla until smooth. Stir in the drained raisins.
5. Whisk the egg whites to soft peaks, then gradually add the remaining 40 g sugar and whisk until glossy but not stiff. Fold gently into the quark mixture.
6. Pour into the pastry case and smooth the top. Bake for 15 minutes, then take the cake out briefly and run a thin knife around the edge between the filling and the pastry rim, to help prevent cracks.
7. Return to the oven and bake for a further 50–60 minutes, until the top is golden and the filling is set at the edges with a slight wobble in the centre.
8. Switch off the oven, open the door a crack and leave the cake to cool inside for 1 hour. Then cool completely at room temperature and chill for at least 3 hours before removing the ring and slicing.

v. Tips & common mistakes

• Drain wet quark. Too much whey makes the filling runny and the base soggy. Leave very soft quark in a muslin-lined sieve for an hour.
• Fold the egg whites gently. They are what make Käsekuchen light. Overmixing knocks the air out and gives a dense, rubbery cake.
• Do not whip the whites stiff. Soft, glossy peaks blend smoothly; stiff whites make lumps and cause dramatic rising and collapse.
• Cool slowly. A sudden change of temperature makes the cake contract and crack. Leaving it in the switched-off oven is the simplest fix.
• Expect a little sinking. A soufflé-like Käsekuchen rises in the oven and settles as it cools; this is normal, not a failure.
• Chill before cutting. Warm Käsekuchen is soft and uneven; a few hours in the refrigerator sets it into clean, creamy slices.

vi. Variations

Käsekuchen ohne Boden is baked without a base, often with a little semolina in the filling. Käsekuchen mit Mandarinen, with tinned mandarin segments folded in, is a classic of German home baking. Russischer Zupfkuchen, despite its name a German invention, combines a cocoa shortcrust base with quark filling and torn pieces of chocolate dough on top. Käsesahnetorte is an unbaked cheesecake of quark and whipped cream set with gelatine between layers of sponge. Saxony's Eierschecke adds a layer of custard over the quark.

Neighbouring countries have their own versions: Polish sernik, made with twaróg, and Austrian Topfenstrudel, which wraps a similar quark filling in stretched pastry. Käsekuchen also sits on the coffee table with Bienenstich and Mohnkuchen; a Mohn-Quark combination is a favourite bakery cake.

vii. Serving & storage

Käsekuchen is served chilled or at cool room temperature, in generous slices, with coffee in the afternoon. It needs no accompaniment, though fresh berries or a fruit compote are sometimes served alongside. Many Germans think it tastes best on the second day, when the filling has fully set.

Keep it covered in the refrigerator, where it keeps for up to four days. It also freezes well: freeze whole or in slices, wrapped tightly, for up to two months, and thaw overnight in the refrigerator. The filling may be very slightly softer after freezing, but the flavour is unchanged.

ix. More from Austrian & German

• Topfenstrudel — quark strudel
• Sernik — Polish cheesecake
• Bienenstich — German bee sting cake
• Mohnkuchen — poppy-seed cake
• Donauwelle — Danube wave cake
• Mango Cheesecake — tropical baked cheesecake