Deep Dark Chocolate Cheesecake

Ingredients

Crust:
24 chocolate wafer cookies (from one 9-ounce package)
1 Tbsp sugar
1/4 cup butter, melted

Filling:
1 9.7-ounce bar 70% Cocoa bittersweet chocolate, chopped
4 (8 oz) packages cream cheese, room temperature
1 1/4 cups plus 2 Tbsp sugar
1/4 cup unsweetened cocoa powder
4 large eggs

Topping:
3/4 cup whipping cream
6 oz 70% cocoa bittersweet chocolate, chopped
1 Tbsp sugar

Bittersweet chocolate curls

Preparation:

Crust:
Preheat oven to 350. Butter 9-in diameter springform pan with 3-in-high sides. Blend cookies in processor until finely ground; blend in sugar. Add melted butter and process until well blended. Press crumbs evenly onto bottom (not sides) of prepared pan. Bake just until set, about 5 minutes. Cool while preparing filling. Maintain oven temperature.

For filling:
Stir chopped chocolate in metal bowl set over saucepan of simmering water until melted and smooth. Remove bowl from over water; cool chocolate until lukewarm but still pourable. Blend cream cheese, sugar, and cocoa powder in processor until smooth. Blend in eggs 1 at a time. Mix in lukewarm chocolate. Pour filling over crust; smooth top. Bake until center is just set and just appears dry, about 1 hour. Cool 5 minutes. Run knife around sides of cake to loosen. Chill overnight.

For topping:
Stir cream, 6 oz chocolate, and sugar in heavey medium saucepan over low heat until smooth. Cool slightly. Pour over center of cheesecake, spreading to within 1/2 in of edge and filling any cracks. Chill until topping is set, about 1 hour.

Release pan sides. Transfer cheesecake to platter. Top with chocolate curls. Let stand 2 hours at room temperature before serving.

Do ahead: Can be made 3 days ahead. Cover with foil and keep refrigerated.