In a medium bowl combine flour, baking powder, and salt; set aside. In a large mixing bowl beat eggs with an electric mixer on high speed for 1 minute. Gradually beat in sugar, beating on high speed for 1 minute. Beat in butter and vanilla seeds or vanilla extract, if using, on low speed until combined. Beat in as much of the flour mixture as you can with the mixer. Stir in any remaining flour mixture with a wooden spoon.
Divide dough into thirds. On a lightly floured surface, roll each portion into a 14x1-1/2-inch log. Arrange logs 2-1/2 inches apart on the prepared cookie sheet.
Bake for 25 minutes or until firm and lightly browned. Cool on cookie sheet on a wire rack for 15 minutes.
Transfer each log to a large cutting board. With a serrated knife, gently slice each log diagonally into 1/2-inch slices. Arrange slices, cut side down, on the cookie sheet.
Bake slices for 10 minutes. Turn slices and bake 10 minutes more or until crisp and lightly browned. Remove and cool on the cookie sheet on a wire rack. Makes 48 cookies.