Process chocolate wafers in a food processor until ground. Add 2 tablespoons sugar and butter; pulse 1 or 2 times. Press crumb mixture into bottom and 1 1/2 inches up sides of a 9-inch springform pan. Chill.
Stir together espresso beans and 1/2 cup boiling water; cool. Pour through a coffee filter, reserving 1/3 cup liquid (add water to make 1/3 cup, if necessary).
Melt chocolate in a small saucepan over low heat, stirring often.
Beat cream cheese at medium speed with an electric mixer until smooth. Gradually add 1 cup sugar, beating well. Add espresso, melted chocolate, sour cream, and eggs; beat until blended. Pour into crust.
Bake at 350° for 55 minutes. Turn off oven, and leave cheesecake in oven 1 hour with oven door slightly open. Cool on a wire rack. Chill at least 8 hours.