PREHEAT oven to 350°F. Line a 13- x 9- x 2- inch baking dish with a 12- x 15-inch sheet of Reynolds Parchment Paper; set aside.
COMBINE flour, sugar, baking powder, baking soda, cinnamon and salt in large bowl. Blend flour mixture and butter until mixture resembles coarse crumbs.
COMBINE sour cream, milk, eggs and vanilla extract; add to dry ingredients. Beat at medium speed with an electric mixer until smooth and fluffy. Spoon half of batter into parchment-lined baking pan. Combine topping ingredients; sprinkle half over batter. Spread remaining batter over topping. Sprinkle with remaining topping.
BAKE 35 to 40 minutes or until wooden toothpick inserted into center comes out