PREHEAT oven to 350°F. Line 13x9-inch baking pan with foil, with ends of foil extending over sides of pan. Grease foil.

PLACE chocolate squares and butter in large microwaveable bowl. Microwave on HIGH 2 min. or until butter is melted. Stir until chocolate is completely melted. Add sugar; mix well. Blend in eggs. Add flour; mix well. Stir in pecans. Spread into prepared pan.

BAKE 30 to 35 min. or until toothpick inserted in center comes out with fudgy crumbs. (Do not overbake.)

MEANWHILE, place caramels and milk in microwaveable bowl. Microwave on HIGH 2-1/2 min., stirring after 1 min. Stir until caramels are completely melted and mixture is well blended. Gently spread over brownie in pan; sprinkle with chocolate chunks. Cool in pan on wire rack. Lift brownies from pan, using foil handles. Cut into 36 squares. Store in tightly covered container at room temperature.