In The Kitchen with Darryl:

Coffee Cake

1 stick margarine - 1 tsp baking soda
1 cup sugar - 1¹ tsp baking powder
2 eggs - 1 cup brown sugar
1 cup sour cream - 2 Tbsp cinnamon
1 tsp vanilla - 2 cups flour

Using an electric mixer, cream together softened margarine and sugar. Beat in 2 eggs. Next beat in the sour cream and vanilla. Now beat in the flour, baking powder, and baking soda. Pour mixture into a greased 9" x 13" pan. In a small bowl mix together the brown sugar and cinnamon, sprinkle evenly on top of the batter, and swirl it in with a butter knife. Bake at 350° for approximately 35 minutes.

PS. I combine one tablespoon of lemon juice with milk and let it sit for five minutes to make the sour cream. This recipe is easy to cut in half and make in an 8" square pan.