Mocha Truffle Cake

Directions

1. 1
   Preheat oven to 350F. Butter a 9-inch springform pan and line bottom with parchment. Butter parchment.
2. 2
   Combine chocolate, sugar and espresso powder in bowl of a food processor. Process until chocolate is finely ground, about 30 seconds. With blades in motion, pour in 3/4 cup boiling water. Process until chocolate has melted, about 20 seconds.
3. 3
   Add butter, eggs and vanilla. Pulse several times to thoroughly mix into a thin batter.
4. 4
   Pour batter into springform and swirl to evenly spread batter.
5. 5
   Bake until set in center, 55 to 60 minutes (cake will appear dry on top and slightly cracked around the edges).
6. 6
   Let cool in pan on a wire rack for 20 minutes; cake may sink in center. Run a thin knife around edges of pan, remove cake from pan, cover and refrigerate until well chilled, at least 2 hours or overnight.
7. 7
   Place cake on a serving plate and let stand at room temperature for 15 to 30 minutes. Just before serving, sift confectioners' sugar over cake.
8. 8
   Serve with whipped cream, if desired.