Mix flour with baking powder, 75 g sugar and vanilla sugar in a bowl. Add 100 g butter in pieces and 1 egg. Knead first with the dough hooks of the mixer and then with your hands to a smooth dough.
Press the dough into a greased square springform pan (approx. 24 x 24 cm) as a base. Chill for about 30 minutes.
Washing and cleaning strawberries. Puree 250 g strawberries with 2 tablespoons of sugar. Put 1 tsp. pudding powder in a bowl, stir gradually with the pureed strawberries until smooth. Dice the remaining fruit finely and mix with the puree.
Mix 100 g butter and 200 g sugar with the whisk of the mixer until smooth. Stir in 3 eggs one after the other. Stir in curd cheese and the rest of the pudding powder as well. Whip cream until stiff, fold in.
Spread the cheese mixture in the mould. Add strawberry puree in patches. Pull through with a fork and marble slightly. Bake in a preheated oven (electric: 175 °C/circulating air: 150 °C/gas: see manufacturer) on the lowest rack for approx. 1 hour.
Cool the cheesecake for about 10 minutes in a switched-off oven with the door slightly open and then let it cool down. Cut into pieces and decorate with chocolate strawberries.