In a large bowl, cream butter and sugar until light and fluffy.
Beat in the eggs, sour cream and vanilla.
Combine the flour, baking powder, baking soda, salt and fruitons® Summer Blend; add to creamed mixture and beat until combined.
Spread half the batter into a greased 8X8-in. baking pan.
In a small bowl, combine topping ingredients; sprinkle half of topping over batter.
Dollop with remaining batter and sprinkle with topping.
Bake at 325° for 40 minutes or until a knife inserted in the center comes out clean.
Cool on a wire rack.