This is a great cookie to make with small children. They love dipping them in sprinkles. The dough also stores well in the refrigerator, so you can make it up well in advance.
1. Melt butter in a 1-1/2 quart (or larger) saucepan. Remove from heat. Add sugar, egg, and vanilla. Beat until smooth, about 1 minute. Sift flour with baking powder and salt over mixture and blend thoroughly.
2. Place pan with dough in refrigerator for 30 minutes.
3. Divide dough in half. Shape each part into a roll 1 1/2 inches thick and wrap in waxed paper. Chill at least 1 hour.
4. Slice into 1/4 inch thick pieces, dip in colored sprinkles or sugar and place on greased cookie sheet. Bake at 350 degrees for 10-12 minutes. Makes 2 dozen cookies. Optional: After slicing, use small cookie cutter to cut out a shape before adding sprinkles.