Topfenstrudel

Soak the raisins in rum and set aside for 15 minutes; press the quark through cheesecloth to drain.

Beat the softened butter with powdered sugar, vanilla, lemon zest, and a pinch of salt.

Mix in the yolks of 6 eggs one at a time, then add the quark, sour cream, lemon juice, and drained raisins.

Whip the whites of 6 eggs with sugar to stiff peaks; gently fold into the cheese mixture, then fold in the flour.

Lay a sheet of strudel dough on a kitchen towel, brush with some of the melted butter, cover with a second sheet and brush again; repeat with the remaining dough.

Spread the filling over the bottom third of the dough, leaving a 3 cm border on each side; fold in the edges and use the towel to roll up the strudel. Place seam-side down on a greased baking sheet.

Brush the top with the remaining melted butter, pierce it a few times, and bake at 170°C for 20 minutes, then at 120°C for another 10 minutes.

Warm up the vanilla sauce, slice the strudel after a short rest, and serve warm.