Preheat oven to 350°F. Mix flour, baking powder, cinnamon and salt in medium bowl. Set aside. Mix brown sugar, butter, eggs, vanilla and pecans in large bowl until well blended. Add flour mixture; mix well. Reserve 1 cup of the batter. Spread remaining batter into lightly greased foil-lined 13x9-inch baking pan. Bake 15 minutes or until firm.
Microwave caramels and milk in microwavable bowl on HIGH 2 to 3 minutes or until caramels are completely melted, stirring after every minute. Cool 5 minutes or until slightly thickened. Pour over baked layer in pan, spreading to within 1/2 inch of edges. Drop reserved 1 cup batter by spoonfuls over caramel layer. Cut through batter with knife several times for marble effect.
Bake 15 to 20 minutes longer or until center is set. Cool in pan on wire rack. Lift from pan. Cut into bars.