Gooey Butter Cookies

1 box butter cake mix
8 ounces cream cheese, softened
1 egg
1/2 cup butter, softened
1/4 teaspoon vanilla
powdered sugar for coating bowl

Combine all ingredients, except powdered sugar, and chill for at least 2 hours. Roll into 1 inch balls and roll in powdered sugar. Bake on ungreased cookie sheet for 10-12 minutes in 350�F oven. Sprinkle with additional powdered sugar when cooled.