Put the biscuits in the freezer bag, close it and crumble finely with a cake roll. Divide into twelve glasses. Sprinkle each with 1 tablespoon of rum.
Wash organic lime hot, dry and finely grate the skin. Cut all limes in half and squeeze. Whip 75 g cream until stiff. Mix mascarpone, quark, 40 g sugar, lime zest and juice and fold in the whipped cream.
Spread the cream into the glasses and refrigerate until serving.
Whip 75 g cream until stiff, pouring in 1 teaspoon of sugar. Pour into a piping bag with a star-shaped spout. Sprinkle cream tuffs onto the mousse before serving and decorate with lime slices or lime zest if desired.