Preheat oven to 350 degrees. Line a 13x9 inch baking pan with foil, with ends of foil extending over sides of pan. Grease foil.
Microwave chocolate and butter in large microwavable bowl on high 2 minutes or until butter is melted. Stir until chocolate is melted. Stir in sugar. Blend in eggs and vanilla. Add flour and nuts, mix well. Spread into prepared pan.
Bake 30-35 minutes or until a toothpick inserted in center comes out with fudgy crumbs. Do no overbake. Cool in pan. Remove brownies from pan using foil as handles. Cut into 24 squares.
CAKE-LIKE Brownies: Prepare as directed, stirring in 1/2 cup milk along with eggs and vanilla and increase flour to 1-1/2 cups.