Cook butter in a small, heavy saucepot over medium heat, stirring constantly, about 6 minutes or until butter begins to turn golden brown. Immediately remove from heat. Pour butter into a bowl. Cover and chill 1 hour or until butter begins to solidify.
Beat butter and cream cheese at medium speed with a mixer until creamy. Gradually add powdered sugar, beating until light and fluffy. Stir in cinnamon and vanilla. Makes 2 cups.