10 HONEY MAID Honey Grahams, broken in half (20 squares), divided
3/4 cup (1-1/2 sticks) butter or margarine
4 squares BAKER'S Unsweetened Chocolate
2 cups sugar
3 eggs
1 tsp. vanilla
1 cup flour
2-1/2 cups JET-PUFFED Miniature Marshmallows
1 cup BAKER'S Semi-Sweet Chocolate Chunks
HEAT oven to 350°F. Line 13x9-inch baking pan with foil; grease foil. Place 15 grahams in pan, overlapping slightly. Break remaining grahams into pieces; set aside.
MICROWAVE butter and chocolate in large microwaveable bowl on HIGH 2 min.; stir until melted. Add sugar, eggs and vanilla; mix well. Stir in flour. Pour over grahams in pan.
BAKE 30 to 32 min. or until toothpick inserted in center comes out with fudgy crumbs. (Do not overbake.) Sprinkle with marshmallows and chocolate chunks. Bake 3 to 5 min. or until marshmallows begin to puff. Press reserved graham pieces gently into marshmallows. Cool. Use foil to remove brownies from pan before cutting to serve.