Sernik

Quark is what gives this cheesecake its light, slightly tangy texture, so cream cheese will make it noticeably denser and richer. If quark is hard to find, well-drained full-fat cottage cheese blended smooth is the closer match, or a mix of cream cheese thinned with a little plain yogurt. Either way keep the total at 500 g so the ratio to the eggs, cream and custard powder stays the same.

The custard powder is the binder here - it thickens the quark filling so it sets instead of weeping. You can replace the 37 g packet with about the same weight of cornstarch plus a teaspoon of vanilla extract and a little extra sugar, since plain cornstarch brings no flavour or sweetness. Don't leave it out altogether or the filling will stay loose even after the full baking time.

Cracks almost always come from too much air beaten into the filling or from cooling too fast. Mix the quark, sugar, eggs and custard powder just until smooth rather than whipping them, and fold in the stiff cream gently. Keep the oven at 160°C the whole time, and let the cake cool gradually in the pan instead of moving it straight into a cold room.

Yes - the recipe already asks for an overnight chill, so it is built to be made ahead. Baked, cooled and refrigerated, it holds well for a couple of days and the filling actually firms up and slices more cleanly on day two. You can also prepare the shortcrust dough in advance and keep it wrapped in the fridge until you're ready to press it into the pan.

Let the cheesecake cool completely in the pan first - warm filling is fragile and the crust is still soft. Because you greased and floured the pan, running a thin knife around the edge before releasing it usually frees any spots where the filling stuck to the sides. If you have a springform, use it: the crust is pressed in firmly and doesn't tip out of a solid pan easily.