Decadent Chocolate Chunk Cheesecake

18 Chocolate Sandwich Cookies, crushed (about 1-1/2 cups)
1/4 cup butter, melted
3 pkg. (8 oz. each) cream cheese, softened
3/4 cup sugar
1/2 cup sour cream
3 eggs
12 squares (1-1/2 pkg. [8 squares each]) Semi-Sweet Baking Chocolate, divided
1/2 cup whipping cream

Preheat oven to 350 degrees if using a 9-in. silver springform pan (or to 325 degrees if using a 9-in. dark nonstick springform pan.) Combine crumbs and butter. Press firmly onto bottom of pan.

Beat cream cheese and sugar in large bowl with electric mixer on medium speed until well blended. Add sour cream; mix well. Add eggs, 1 at a time, beating on low speed after each addition just until blended. Chop 8 of the squares of chocolate; stir into batter. Pour over crust. Bake 45 to 50 minutes or until center is almost set. Run knife or metal spatula around side of pan to loosen cake. Cool completely.

Chop remaining 4 squares of chocolate. Bring cream to simmer in small saucepan on low heat. Remove from heat. Add chocolate; stir until completely melted. Cool slightly. Pour over cheesecake. Refrigerate at least 3 hours or overnight. Remove side of pan before serving. Store leftover cheesecake in refrigerator. Makes 16 servings