Step 1Grease 9-inch springform pan and wrap double thickness of foil around outside. Mix cookie crumbs and butter and press evenly into bottom of pan.
Step 1Beat cream cheese at medium speed until smooth. Gradually add sugar. Beat until light and fluffy, 2 minutes. Add eggs, 1 at a time, mixing each just until combined before adding another. Scrape down sides of bowl. Add sour cream, whipping cream and vanilla. Transfer 1-cup batter to small bowl; set aside. Add peanut butter to remaining batter and mix well, scraping down bowl.
Step 2Add melted chocolate to reserved 1-cup batter. Pour over crumb crust; spread smooth. Pour peanut butter batter over. Smooth top. Set into 2-inch deep baking dish and pour in enough hot water to come up sides 1 inch.
Step 3Bake at 350 degrees until toothpick inserted in center comes out clean, top has risen to top of pan and is golden brown, about 1 hour 5 minutes. Remove from water bath; cool completely on rack. Use small flexible knife to release cheesecake from sides of pan. Leave ring on while storing. Refrigerate overnight, covered airtight.
Step 4To serve, bring to room temperature. Use sharp knife dipped into hot water to cut in wedges.