Mix the flour with baking powder, then add sugar, vanilla sugar and salt. Form into a mound with a hollow in the middle. Pour the butter and eggs into it and knead to a dough. Knead in the chopped almonds. Form the dough to a ball, adding more flour if necessary. Cover and chill for 30 minutes.
Line a baking tray with baking parchment and preheat oven to 200 C / Gas 6.
Cut dough into 6 pieces and shape each into a 25cm log. Arrange logs on a baking tray, leaving enough space for them to spread whilst cooking. Bake in preheated oven for 10-15 minutes.
Allow them to cool a little, then cut into 1cm slices. Lay on a baking tray and bake for another 8-10 minutes at 200 C / Gas 6 until golden-brown.