Step 1

Pulse cookie crumbs and granulated sugar in food processor until fine. Place in a large bowl and toss with melted butter until moistened. Firmly press into the bottom and 1 1/2-inches up sides of an 8-inch springform pan.

Step 2

Using a mixer fitted with a paddle attachment, beat cream cheese and sugar on medium speed until light and creamy, about 1 minute, scraping down sides of bowl as necessary. Reduce speed to low and mix in vanilla, sour cream, and melted chocolate until smooth and homogenous.

Step 3

Spoon mixture into crust and smooth top. Chill until set, about 4 hours. Dust with cocoa powder and let sit for 30 minutes at room temperature before serving.