For the curd forest berry slice, first separate the eggs. Beat the egg whites until stiff. Beat the egg yolks with the granulated sugar until foamy.
Puree raspberries with raspberry liqueur and whipped cream with a hand blender. Mix into the yolk mixture. Stir in custard powder and curd. Carefully fold in beaten egg whites.
Line a small baking dish (approx. 22 x 28 cm) with the wholemeal butter cookies and spread the curd mixture on top.
Bake in the oven at 170 °C.