Melt 150 g butter. Finely crumble 400 g biscuits, mix with the butter. Grease half of the fat pan of the oven (approx. 36 x 40 cm). Add the crumb mixture and press it to a flat bottom.
Fold a piece of foil into a strip of approx. 5 x 20 cm, place it on the edge of the floor as a border. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 8 minutes, allow to cool.
For the cookie dough, mix 50 g soft butter with brown sugar, 25 g white sugar and salt until creamy. Stir in flour and knead in 50 g chocolate drops, put aside. Chop 200 g cookies into pieces.
For the cheese mixture, stir cream cheese, sour cream, 100 g sugar and vanilla until smooth. Stir in the starch and eggs one after the other, fold in the cookie pieces. Spread the mixture on the base. Pluck the cookie dough into small pieces and spread on the cheese mixture.
Sprinkle with remaining chocolate drops. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 40-45 minutes. Let cool on a cake rack and cut into pieces.