Heat oven to 350. Heat Peanut butter, 3 tbls sugar, and margarine in 1 1/2 qt saucepan over low heat, stirring frequently until margarine is melted. Stir in crracker crumbs. Press firmly against bottom and side of ungreased pie plate (9 X 1 1/4). Beat cream cheese slightly in 2 1/2 qt bowl. Add 3/4 cup sugar, 2 tsp vanilla and eggs; beat on medium speed until smooth, about 2 minutes. Fold in peanuts; pour over crumb mixture. Bake until firm, about 30 minutes. Cover and refrigerate at least 2 hours but no longer than 48 hours. Beat whipping cream and 1/2 tsp vanilla in chilled bowl until stiff. Spread over cheesecake, sprinkle with peanut brittle. Refrigerate immediately. 8 servings; 410 calories per serving.
