Preheat oven to 350~. Microwave unsweetened chocolate and 3/4 c. margarine in large microwaveable bowl on HIGH 2 minutes or until margarine is melted. STIR UNTIL CHOCOLATE IS COMPLETELY MELTED. Stir granulated sugar into melted chocolate mixture. Mix in eggs and 1 t. vanilla until well blended. Stir in flour and peanuts. Spread batter in greased 13x9" pan. Bake for 30-35 minutes or until toothpick inserted in center comes out with fudgey crumbs. DO NOT OVERBAKE! Cool in pan. Mix peanut butter, powdered sugar and 1 t. vanilla in separate bowl until well blended and smooth. Spread over brownies. Microwave semi-sweet chocolate and 1/4 c. margarine in small microwaveable bowl on HIGH for 2 minutes or until margarine is melted. STIR UNTIL CHOCOLATE IS COMPLETELY MELTED. Spread over peanut butter layer. Cool until set. Cut into squares.