Preheat oven to 350 degrees F. Beat butter until fluffy. Beat in cornstarch and sugar and then blend in flour. Form dough into walnut sized balls and roll lightly in colored sprinkles. Place on a non greased cookie sheet. Very slightly flatten with the bottom of a glass. Bake at 350 degrees F for 12 minutes but do not allow to brown.
Source: Can't remember where I found this recipe because have used it for a couple of years.
By Deeli from Richland, WA