Devils Food Cake with Mint Chocolate Ganache

Directions

1. 1
   Preheat the oven to 350F.
2. 2
   Butter two 9-by-2-inch round cake pans; line bottoms with parchment paper.
3. 3
   Butter parchment; dust with cocoa powder, tapping out excess.
4. 4
   In a medium bowl, whisk cocoa with hot water until smooth.
5. 5
   Whisk in sour cream; let cool.
6. 6
   Into a medium bowl, sift together flour, baking soda, and salt; set aside.
7. 7
   In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium speed until light and fluffy, 3 to 4 minutes.
8. 8
   Add eggs, one at a time, beating to combine after each; scrape down sides of bowl as needed.
9. 9
   Beat in vanilla.
10. 10
    With mixer on low speed, add flour mixture in two parts, alternating with the cocoa mixture and beginning and ending with the flour; beat until combined.
11. 11
    Divide batter between prepared pans; smooth with an offset spatula.
12. 12
    Bake until a cake tester inserted in centers comes out clean, 45 to 50 minutes.
13. 13
    Transfer pans to a wire rack to cool 15 minutes.
14. 14
    Invert cakes onto rack; peel off parchment.
15. 15
    Reinvert cakes; let cool completely, top sides up.
16. 16
    Transfer half of Mint-Chocolate Ganache (3 1/2 cups) to clean bowl of an electric mixer; set aside remaining.
17. 17
    Let cool completely, stirring frequently, about 40 minutes.
18. 18
    Attach bowl to mixer fitted with whisk attachment.
19. 19
    Beat on medium-high speed until ganache holds soft peaks, 5 to 7 minutes.
20. 20
    Using a serrated knife, trim tops of cake layers to make level.
21. 21
    Transfer one of the layers to a cake turntable or platter, and spread top with 1 1/2 cups whipped ganache.
22. 22
    Top with remaining layer, cut side down, and spread remaining whipped ganache in a thin layer over entire cake, covering completely.
23. 23
    Refrigerate until set, about 30 minutes.
24. 24
    Transfer cake to a wire rack set over a rimmed baking sheet.
25. 25
    Pour the reserved ganache over the top, letting it run down the sides.
26. 26
    If necessary, use a large offset spatula to spread from the center toward the edges, so that the cake is evenly and completely covered.
27. 27
    Refrigerate until the ganache has just begun to set, about 30 minutes.
28. 28
    Transfer cake to a serving plate, and garnish with Chocolate Mint Leaves.
29. 29
    Serve immediately, or refrigerate, covered with a cake dome, for up to 2 days.
30. 30
    Using a small pastry brush, coat underside of each leaf with a thick layer of chocolate.
31. 31
    (If chocolate drips onto the top of the leaf, gently wipe it away with your finger.)
32. 32
    Drape the leaves, chocolate sides up, over the handle of a wooden spoon set on a parchment-lined baking sheet.
33. 33
    Refrigerate until set, about 10 minutes.
34. 34
    Gently grasp the chocolate layer of each leaf with kitchen tweezers.
35. 35
    Holding the stem, peel off mint leaf.
36. 36
    Chocolate leaves can be kept in an airtight container in the refrigerator for up to 2 days.
37. 37
    When pans are prepared for baking chocolate cakes, they are dusted with cocoa powder rather than flour, which may leave white streaks on the finished dark cake.