Use an electric mixer and beat butter or margarine until soft. Add 3/4 cup sugar and beat until fluffy. Add egg and vanilla or almond flavoring and beat again. Mix flour, baking powder, and salt together and add to butter-sugar-egg mixture a little bit at a time. Divide the dough into 2 parts, wrap in plastic wrap and put in the refrigerator for 30 minutes to get hard enough to play with like modeling clay. Then make small balls of dough and roll into ropes. Shape the ropes into numbers or letters on an ungreased cookie sheet, leaving a little space between them. Brush with a little milk, sprinkle on a bit of sugar and bake at 375 degrees F for about 10 minutes. Cool on a rack.