Sift flour and measure. Add cinnamon and baking powder and sift 3 times.
Cream butter. Add sugars, a little at a time, and beat until light and fluffy. Add the eggs and beat thoroughly. Fold in the ground nuts.
Add flour gradually and mix well. Shape the dough in rolls about 1½ inches thick. Refrigerate them for at least 12 hours. Slice very thin.
Bake 10 minutes on greased baking sheets in a preheated 400° oven.