1 1/4 cups butter (no substitutions), softened
2 1/4 cups confectioners' sugar
1/3 cup baking cocoa
1/4 cup sour cream
1 tablespoon vanilla extract
2 1/4 cups all-purpose flour
2 cups semisweet chocolate chips
1/4 cup chocolate sprinkles

In a large mixing bowl, cream butter, sugar and cocoa until light and fluffy. Beat in sour cream and vanilla. Add flour; mix well. Stir in chocolate chips. Refrigerate for 1 hour.
Shape into 1-in. balls; dip in chocolate sprinkles. Place, sprinkled side up, 2 in. apart on ungreased baking sheets.
Bake at 325 degrees for 10 minutes or until set. Cool for 5 minutes before removing to wire racks to cool completely.