In a large bowl, cream together the butter and sugar until fluffy. Beat in the eggs one at a time, then stir in the vanilla and lemon extracts. Combine the flour, baking powder, and salt; gradually blend into the creamed mixture to form a soft dough. Cover or wrap dough, and refrigerate overnight.
Preheat the oven to 400 degrees F (200 degrees C). On a floured surface, roll the dough out 1/4 inch thick. Cut into desired shapes using cookie cutters. Place cookies 2 inches apart on ungreased cookie sheets.
Bake for 10 minutes in the preheated oven, or until lightly browned. Cool on wire racks.