Heat oven to 350-F. Combine crumbs and margarine; press firmly on bottom of 9-inch springform pan. In large mixer bowl, beat cheese until fluffy. Gradually beat in sweetened condensed milk until smooth. Add eggs, flour and vanilla; mix well. Divide batter in half. Add chocolate to one half of batter; mix well. Pour into prepared pan. Top evenly with vanilla batter. Bake 50 to 55 minutes or until center springs back when lightly touched. Cool. Top wlth Chocolate Glaze. Refrigerate leftovers. (Makes 12 servings) chocolate Glaze: in small saucepan, over low heat, melt 2 (1-ounce) squares semi-sweet chocolate with 1/4 cup whipping cream. Cook and stir until thickened and smooth. Remove from heat; spread over cheesecake. (Makes about 1/3 cup) Tip: Glaze can be doubled. Recipe by: Family Circle Posted to MC-Recipe Digest V1 #935 by "Nitro_II " on Nov 30, 97