Preparation / Directions:
Place graham cracker crumbs, brown sugar, and butter in bowl. Attach bowl and flat beater. Turn to speed 2 and mix 30 seconds. Press mixture into bottom of 9-inch springform pan.
Place cream cheese, vanilla, and sugar in clean bowl. Attach bowl and flat beater. Turn to speed 6 and beat 2 minutes, until fluffy. Stop and scrape bowl. Turn to speed 4 and beat 15 seconds.
Pour 1/3 of cream cheese mixture into a small bowl. Add chocolate and mix well. Drop chocolate and plain batter by the spoonful into prepared pan. Swirl lighlty with a knife. Bake at 325 F for 1 hour 30 minutes. Cool on wire rack 30 minutes, then refrigerate at least 2 hours.