HEAT oven to 350° MICROWAVE chocolate and margarine in large microwavable bowl at HIGH 2 minutes or until margarine is melted. Stir until chocolate is completely melted. STIR sugar into chocolate. Mix in eggs and vanilla until well blended. Stir in flour and nuts. Spread in greased 13x9-inch pan. BAKE 30 to 35 minutes or until toothpick inserted in center comes out with fudgy crumbs. Cool in pan; cut into squares. Makes 24 fudgy brownies. Note: When using glass baking dish, bake at 325 degrees F. For cakelike brownies, stir in 1/2 cup milk with eggs; use 1-1/2 cups flour. cook 042