In a large bowl, cream butter and sugars until light and fluffy. Beat in egg. Combine the flour, baking powder, baking soda and cinnamon; gradually add to creamed mixture alternately with buttermilk. beating well after each addition. , Spread into a greased 8-in. square baking pan. Combine topping ingredients; sprinkle over batter. Cover and refrigerate overnight. , Bake, uncovered, at 350° for 40-45 minutes or until a toothpick inserted in the center comes out clean. Cool on a wire rack.