In a large mixing bowl, combine the softened butter, sugar, and vanilla sugar. Beat them together until the mixture is smooth and fluffy.

In another bowl, sift together the flour and baking powder. Gradually add this into the butter mixture, stirring until a smooth dough forms.

Next, fold in the ground hazelnuts gently until evenly incorporated into the dough.

Spread the dough evenly onto a greased baking sheet.

Bake in a preheated oven at 180 °C (350 °F) for about 20 minutes or until the edges are golden brown.

Once out of the oven, let the dough cool slightly before spreading the warm apricot jam evenly across the top.

Melt the dark chocolate and drizzle it generously over the apricot jam, ensuring every corner gets a dose of rich goodness.

Chop the whole hazelnuts roughly and sprinkle them on top for a crunchy finish.

Finally, cut the baked treat into triangles and they’re ready to serve!