Heat oven to 350° F. In medium bowl, mix flour, baking powder, cinnamon and salt. Set aside.
In large bowl, mix brown sugar, butter, eggs, vanilla and pecans until well blended. Add flour mixture; mix well. Reserve 1 cup batter. Spread remaining batter into lightly greased, foil-lined, 13-by-9-inch baking pan. Bake 15 minutes, or until firm.
In microwavable bowl, microwave caramels and milk on high 2-3 minutes, or until caramels are completely melted, stirring after each minute. Cool 5 minutes, or until slightly thickened. Pour over baked layer in pan, spreading to within 1/2 inch of edges. Drop reserved batter by spoonfuls over caramel layer. With knife, cut through batter several times for marble effect.
Bake 15-20 minutes, or until center is set. Cool in pan on wire rack. Lift from pan. Cut into bars.