Triple Chocolate Cheesecake (for the Chocolate Lover)

Triple Chocolate Cheesecake (for the Chocolate Lover)
Ingredients for Crust:
2 1/3 cups graham cracker crumbs
1/3 cup sugar
½ cup butter, melted    
Ingredients for Cheesecake:
6 ounces milk chocolate morsels
½ cup butter, divided
1 ½ (4 ounce) bars bittersweet chocolate, chopped
4 (8 ounce) packages cream cheese, softened
2 cups sugar
1 tablespoon vanilla extract
4 large eggs
1 cup sour cream
2 tablespoons cocoa powder
Garnish:  Whipped cream and chocolate squares 
 
Directions:

1.  Preheat oven to 300 degrees.
2. To prepare crust: In a medium bowl, combine cracker crumbs and sugar.  Add melted butter, stirring to combine.  Press mixture into bottom and 1 inch up sides of a 10-inch springform pan.  Bake for 6 minutes.
3. To prepare cheesecake:  in a small saucepan, combine chocolate morsels and ¼ cup butter.  Cook over medium-low heat, stirring constantly, until smooth.  Spoon mixture into a medium bowl; set aside. 
4. In a small saucepan, combine chopped bittersweet chocolate and remaining ¼ cup butter.  Cook over medium-low heat, stirring constantly, until smooth.  Spoon mixture into a separate medium bowl; set aside.
5. In a large bowl, beat cream cheese, sugar and vanilla at medium speed with a mixer until creamy.  Add eggs, one at a time, beating well after each addition.  Stir in sour cream.  Spoon half of batter into milk chocolate mixture, stirring to combine.
6.  Stir remaining half of batter into bittersweet chocolate mixture, stirring to combine.  Add cocoa into bittersweet chocolate mixture.
7. Spoon milk chocolate mixture into prepared crust.  Spoon bittersweet chocolate mixture over milk chocolate mixture.  Bake for 1 hour.
8. Turn oven off, and let cheesecake stand in oven with the door closed for 1 hour.
9. Remove from oven; cool for 2 hours on a wire rack. 
10. Chill for at least 4 hours before serving. Garnish with whipping cream and chocolate squares if desired.
11. Store cheesecake, covered, in refrigerator up to three days.