Italian-Style Chocolate Hazelnut Cheesecake - cooking recipe

Ingredients

Crust
1 cup reduced-fat whole wheat cracker, finely crushed (such as McVitie's brand or Carr's whole wheat crackers)
1 ounce fine-quality bittersweet chocolate, grated (no more than 60% cacao if marked)
1/4 cup unsalted butter, melted
Filling
1/2 lb fine-quality bittersweet chocolate, chopped (no more than 60% cacao if marked)
8 tablespoons unsalted butter, cut into pieces
18 ounces cream cheese, at room temperature
1/2 cup sour cream
1/4 teaspoon pure vanilla extract
2 large eggs
2/3 cup superfine sugar
1 cup hazelnuts, toasted loose skins rubbed off in a kitchen towel while still warm, and nuts chopped (4 1/2 ounces)

Preparation

Crust:
Combine all ingredients, then press onto bottom of springform pan.
Filling:
Preheat oven to 325\u00b0F with rack in middle.
Melt chocolate with butter, then remove from heat and whisk in cream cheese until smooth. Whisk in sour cream and vanilla.
Whisk together eggs and sugar in a large bowl until mixture has a mousse-like consistency, then stir in chocolate mixture and nuts.
Pour filling into crust and bake 1 1/2 hours. (Top will be slightly cracked.)
Cool to room temperature in pan on a rack, about 1 hour, then chill at least 1 hour. (Cake will sink slightly.).