Cream butter (or margarine) and sugar. Add eggs and vanilla and mix till fluffy. Sift flour, baking powder, and salt, and add to creamed mixture. Refrigerate dough till chilled. Roll out 1/4-inch thick on lightly floured board or pastry cloth. Cut with bell-shaped cookie cutter. Place on greased cookie sheet and bake at 350 degrees F. for 12 to 15 minutes. Cool on wire rack. Frost with red- or green-tinted powdered sugar icing. Store in covered container. Makes 5 dozen cookies.