HEAT oven to 350°F.
MICROWAVE chocolate and butter in large microwaveable bowl on HIGH 2 min. or until butter is melted. Stir until chocolate is completely melted. Add sugar; stir until well blended. Add eggs and vanilla; mix well. Stir in flour. Spread into greased 9-inch pie plate.
BAKE for 30 min. or until toothpick inserted in centre comes out clean. Cool completely on wire rack. Scoop out centre of brownie with spoon, leaving 1/2-inch-thick rim around edge and thin layer of brownie on bottom. Reserve removed brownie pieces for later use.
POUR milk into large bowl. Add pudding mixes. Beat with wire whisk 2 min. or until well blended. (Mixture will be thick.) Gently stir in 1 cup of the whipped topping and all but 1/2 cup of the removed brownie pieces. Spoon into brownie crust; top with remaining 3/4 cup whipped topping and reserved brownie pieces. Refrigerate 2 hours or until set.
