Peanut Butter Cup Swirl Cheesecake

Crust:
1 1/2 cups chocolate wafer cookie crumbs
4 tablespoons butter, melted

Filling:
4 packages (8-ounce) cream cheese, softened
1 cup creamy peanut butter
1 cup sugar
4 large eggs (at room temperature)
1/2 cup sour cream
2 teaspoons vanilla extract
3 ounces bittersweet chocolate, melted
6 regular-size peanut butter cups, quartered

Crust:
Heat oven to 350 degrees. Coat a 9-inch springform pan with cooking spray; tightly cover outside of pan with a double thickness of foil. Combine cookie crumbs and butter in a bowl until crumbs are evenly moistened. Press into bottom and 1/2 inch up the sides of prepared pan. Bake 10 minutes; let cool on a wire rack.

Filling:
In a large bowl, beat cream cheese with an electric mixer on medium-high speed, until light and fluffy. Gradually beat in sugar until smooth. Add eggs, 1 at a time, until just blended. Beat in sour cream and vanilla. Remove 1 1/2 cups of the batter to a medium bowl; stir in chocolate. Add peanut butter to cream cheese mixture in large bowl and beat until smooth. Remove 1 3/4 cups of the peanut butter batter to a medium bowl and reserve.
Spoon the remaining peanut butter batter over crust in pan. Top evenly with peanut butter cups, gently pressing pieces into batter. Alternately drop reserved chocolate batter and reserved peanut butter batter on top of peanut butter cups to cover; swirl batters together with a skewer or a knife to marbleize.
Place cheesecake in a larger baking pan and place on oven rack. Carefully pour enough hot water into larger pan to reach 1 inch up sides of springform pan. Bake 1 hour, or until cake barely jiggles in the center.
Remove cheesecake from water bath; remove foil. Using a thin knife, carefully cut around top edge of cake where it meets the pan to release. Let cool completely on wire rack. Cover and refrigerate until cold, 6 hours or overnight.
To serve, run a sharp knife around edge of pan to loosen and remove side of pan.