To prepare Brownie layer: Melt chocolate and margarine over very low heat or melt in microwave on HIGH for 2 minutes or until margarine is melted then stir until chocolate is completely melted. Stir sugar into chocolate, add eggs and vanilla stir until completely mixed. Mix in flour until well blended. Stir in nuts. Spread in greased 20 cm pan To prepare cheese topping: Mix cream cheese, sugar, egg and flour until smooth. Spoon over brownie mixture, swirl with knife to marbelize. Bake at 180ºC or 35 minutes or until wooden pick inserted in center comes out almost clean (DO NOT OVERBAKE). Cool in pan; cut into squares. Makes 16 brownies.