Sort blueberries, wash. Heat 100 g berries and jam in a saucepan, puree finely and let cool off.
Place paper cups in the twelve troughs of a muffin tray. Melt butter in a pot. Place cookies in a freezer bag, seal and crumble with a pastry roll. Mix butter and cookie crumbs, distribute evenly in the tins. Press down as a base, pull up a small rim and refrigerate for about 30 minutes.
Soak gelatine in cold water. Mix mascarpone, quark, sugar, vanilla sugar, lemon peel and juice. Whip 200 g cream until stiff.
Squeeze out the gelatine and dissolve carefully in a small pot at low heat. Stir in 2-3 tablespoons of mascarpone cream, then stir everything into the remaining cream. Carefully fold in the whipped cream. Loosely fold in 5 tbsp. blueberry puree, so that a light marbling is created. Spread the mascarpone cream into the muffin cups and chill for approx. 3 hours.
Whip 200 g cream until stiff. Lift the blueberry muffins out of the muffin tray, remove the paper cups and place the muffins on a cake plate. Spoon the cream loosely onto the cake plate. Pile the remaining blueberries on the cream and sprinkle with the remaining blueberry puree.