Microwave chocolate and butter in a 2-quart glass bowl at HIGH 1 1/2 minutes or until melted, stirring twice. Add sugar and eggs, stirring until blended. Stir in flour and chopped pecans. Pour into a lightly greased, aluminum foil-lined 13- x 9-inch pan.
Bake at 350° for 20 to 23 minutes. Cool on a wire rack 1 hour.
Spread cooled brownies with Vanilla Cream Topping; chill 45 minutes. Pour Brownie Glaze over Vanilla Cream Topping, and spread evenly. Chill 1 hour. Let stand at room temperature 15 minutes; cut into 1-inch squares.
Vanilla Cream Topping: Stir together butter, sugar, half-and-half, and vanilla until smooth.
Brownie Glaze: Microwave chocolate squares and butter in a 1-quart glass bowl at HIGH 1 1/2 minutes or until melted, stirring twice.