Chop candy. Heat the cream in a pot while stirring until the sweets have dissolved. Pour caramel cream into a bowl. Let it cool down. Chill overnight.
Grease a springform pan (26 cm; approx. 8 cm high) and dust with flour. Cream butter, 75 g sugar, 1 packet of vanilla sugar and 1 pinch of salt. Stir in 1 egg. Mix flour, nuts and baking powder and stir in briefly, alternating with the milk.
Spread the dough into the mould. Chill for about 10 minutes.
Mix 250 g quark, starch, 125 g sugar, 1 sachet vanilla sugar and caramel spread. First stir in 750 g quark, then 5 eggs one by one.
Spread the curd mixture on the sponge mixture in the mould. Bake in a preheated oven (electric oven: 175 °C/circulating air: 150 °C/gas: level 2) 1 1⁄4-1 1⁄2 for several hours. Then allow to cool in the mould on a cake rack.
Whip the caramel cream with the whisk of the hand mixer until creamy (does not become as firm as whipped cream). Spread loosely on the cake and refrigerate for about 1 hour. Dust with cocoa shortly before serving.