Step 1

Line 13x9-inch pan with foil, with ends of foil extending over sides; spray with cooking spray. Microwave chocolate and 1 cup butter in large microwaveable bowl on HIGH 2 to 2-1/2 min. or until butter is melted; stir until chocolate is completely melted and mixture is well blended.

Step 2

Stir 1-1/4 cups sugar into chocolate until blended. Mix in 5 eggs and 1 tsp. vanilla. Stir in flour and baking powder until blended. Add nuts. Spread about 2/3 of the batter onto bottom of prepared pan.

Step 3

Beat cream cheese, remaining butter, sugar, eggs, vanilla and jam in large bowl with mixer until blended. Pour over brownie mixture; top with spoonfuls of remaining chocolate batter. Swirl gently with knife.

Step 4

Bake 1 hour 5 min. to 1 hour 15 min. or until toothpick inserted in center comes out with fudgy crumbs. (Do not overbake.) Cool in pan. Refrigerate 3 hours or until chilled. Use foil handles to lift dessert from pan before cutting into squares to serve.