Cream Cheese Cookies
["1/4 c. butter or margarine", "1 (8 oz.) pkg. cream cheese, softened", "1 egg yolk", "1/4 tsp. vanilla", "1 pkg. yellow devil's food cake mix"]
["Cream butter and cream cheese.", "Blend egg yolk and vanilla. Add cake mix 1/3 at a time.", "Cover.", "Chill for 30 minutes.", "Bake at 375\u00b0."]
["butter", "cream cheese", "egg yolk", "vanilla", "cake mix"]