Place a greased 9-in. springform pan on a double thickness of heavy-duty foil (about 18 in. square). Securely wrap foil around pan. Combine cookie crumbs and butter; press onto the bottom of prepared pan.
In a large bowl, beat cream cheese and sugar until smooth. Beat in sour cream and vanilla. Add eggs; beat on low speed just until combined. Set aside 1-1/2 cups; pour remaining batter over crust.
In a microwave-safe bowl, melt chocolate; stir in preserves until blended. Stir in reserved batter just until blended. Drop by tablespoonfuls over the plain batter (do not swirl). Place springform pan in a large baking pan; add 1 in. of hot water to larger pan.
Bake at 325° for 65-75 minutes or until center is just set and top appears dull. Remove springform pan from water bath. Cool on a wire rack for 10 minutes. Carefully run a knife around edge of pan to loosen; cool 1 hour longer.
For topping, place chocolate in a small bowl. In a small saucepan, bring cream just to a boil. Pour over chocolate; whisk until smooth. Cool slightly. Spread over top of cheesecake. Refrigerate overnight. Garnish with raspberries and whipped cream if desired. Remove sides of pan.Yield:16 servings.