PREHEAT oven to 350°F. Grease 13×9-inch baking pan.
For Topping
COMBINE brown sugar, flour and butter in small bowl with pastry blender or two knives until crumbly. Stir in nuts and 1/2 cup morsels.
For Cake
COMBINE flour, baking powder, baking soda and salt in small bowl. Beat granulated sugar, butter and vanilla extract in large mixer bowl until creamy. Add eggs, one at a time, beating well after each addition. Gradually add flour mixture alternately with sour cream. Fold in remaining 1-1/2 cups morsels. Spread into prepared baking pan; sprinkle with topping.
BAKE for 25 to 35 minutes or until wooden pick inserted in center comes out clean. Cool in pan on wire rack.
Click here for printable version