Ingredients:
In large bowl, cream together the butter and sugar. Add eggs, vanilla, and liqueur. Blend well. In separate bowl, combine the flour, salt, and baking powder. Add the hazelnuts to the egg mixture. Add the flour and stir until just blended.
On a floured surface, roll the dough into a cylinder 1 3/4 inches by diameter by 12 inches in length. Place the dough on a cookie sheet and bake in 325 degree oven for about 25 minutes. Allow to cool for 5 minutes. Diagonally slice the roll into ½ inch cookies, and place face side up on the cookie sheet. Bake for 10 minutes. Cool overnight.