And this is how to do it:
Heat oven to 350°F.
Beat cream cheese, sugar and vanilla with mixer until well blended. Add eggs, 1 at a time, beating on low speed after each just until blended.
Remove 1 cup batter; mix with melted chocolate. Pour plain batter in to crust first. Top with chocolate batter.
Bake 40 min. or until center is almost set. Cool completely. Refrigerate 3 hours. Top with Cool Whip and berries (if desired) just before serving.
There you go! Yey!;)