2. Cream butter and sugar in a large bowl. Add baking powder and egg yolks, one at a time. When yolks are blended, add flour, 1 cup at a time, blending to form soft dough.
3. In another bowl, beat egg whites until fluffy but not stiff.
4. Shape dough into round, flattened balls 1 inch in diameter. Dip each cookie into beaten egg whites and then roll in chopped almonds. Make a groove in the center of each cookie and place on an ungreased cookie sheet about 1 inch apart.
5. Bake for 20 to 25 minutes, or until lightly golden. Let cool on the sheet and then dip in confectioners' sugar. Place ¼ teaspoon preserves in the center of each cookie.
