Whipped Shortbread

1 pound (500 g) butter
3/4 cup (175 mL) sugar (half brown, half confectioners')
4 cups (1 L) all-purpose flour

Using an electric mixer, beat the butter and sugar well. Slowly add the flour. When completely combined, drop the dough by teaspoon onto the cookie sheets. Bake at 325 degrees F (160 degrees C) for 10 to 12 minutes. Do not allow to brown.