HEAT oven to 350 degrees F. Combine cookie crumbs and butter in small bowl; press firmly into bottom of 9-inch springform pan.
BEAT cream cheese in large bowl 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 is set. Cool. Top with Chocolate Glaze. Chill.
MELT chocolate with cream in small saucepan over low heat. Cook and stir until thickened and smooth. Remove from heat; spread over cheesecake. Makes about 1/3 cup (recipe can be doubled, if desired, for thicker glaze).