Mix together low-fat quark, cream cheese, cream, 500 g sugar, vanilla sugar and cream stabilizer.
For the brittle, heat 50 g butter and 4 tablespoons sugar in the pan until the sugar has melted. Add the almond flakes and brown while stirring. Caution: do not let it get too dark and spread it straight out of the pan on aluminum foil or a baking sheet, as the brittle will brown or burn in the hot pan. Possibly break into smaller pieces (e.g. in a freezer bag).
Put the quark mixture in layers with blackberries in a glass bowl. Sprinkle the brittle on top. Chill until ready to eat.
Note: If you like the dessert to be thinner, you can use more cream.