Heat oven to 375 degrees. Combine sugar, butter, egg yolk and almond extract in a large bowl. Beat at medium speed, scraping bowl often until mixture is light and fluffy (2-3 minutes). Continue beating, gradually adding flour and cocoa, until well mixed (2-3 minutes). Shape rounded teaspoonfuls of dough into 1 inch balls. Place about an inch apart on cookie sheets. (shape balls or make sugar dipped glass or make thumbprint indentations). Bake 7-9 minutes or until set. Cool completely. Coat with melted chocolate or vanilla coating and decorate with chopped nuts, candy, coconut, preserves or colored sugar, as desired.