Cream butter, ¾ cup sugar and vanilla in mixer bowl. Add 3 eggs, beating well. Combine flour, baking powder and baking soda. Add dry ingredients to butter mixture alternately with sour cream. Combine pumpkin, beaten egg, ½ cup sugar and pie spice. Spoon half of batter into 13 x 9 inch pan; spread to corners. Sprinkle half of streusel over batter. Spread pumpkin mixture over streusel. Carefully spread remaining batter over pumpkin mixture. Sprinkle remaining streusel over top. Bake at 325 degrees for 50 to 60 minutes or until toothpick inserted in center comes out clean.
Yield: Makes 12 servings.
Cut brown sugar, butter and cinnamon together until blended. Stir in nuts.