Basic Chocolate Cake

Directions

1. 1
   Preheat the oven to 350F, with racks in the upper and lower thirds.
2. 2
   Cut 2 8-inch rounds of parchment paper to line the bottoms of 2 8-inch (2 inches deep) round cake pans.
3. 3
   Butter and line the pans.
4. 4
   Butter the linings.
5. 5
   Dust the pans with cocoa, tapping out excess.
6. 6
   Set aside.
7. 7
   Sift together the cocoa, flour, sugar, baking soda, baking powder, and salt into the bowl of an electric mixer.
8. 8
   Return the bowl to the mixer.
9. 9
   Fit the mixer with the paddle attachment.
10. 10
    Add the eggs, yolk, warm water, buttermilk, oil, and vanilla.
11. 11
    Mix on low speed until smooth, about 3 minutes.
12. 12
    Divide the batter evenly between the prepared pans.
13. 13
    Bake, switching the positions of the pans and rotating them halfway through, until a cake tester inserted into the centers comes out clean, about 40 minutes.
14. 14
    Let cool in the pans on wire racks 30 minutes.
15. 15
    Run a thin knife around the edges of the cakes to loosen.
16. 16
    Unmold; peel off the parchment.
17. 17
    Let cool completely, top sides up, on the racks.
18. 18
    Trim the tops of the cake layers with a long serrated knife to make them level.
19. 19
    Using a small offset spatula, cover the top of one cake layer evenly with 1 1/2 cups frosting; spread the frosting so it extends just beyond the edges of the cake.
20. 20
    Place the second layer, cut side down, on top; press gently to level.
21. 21
    Frost the top and sides of the assembled cake with the remaining frosting.
22. 22
    Put the sugar in the bowl of a food processor, and scrape in the vanilla seeds.
23. 23
    Process until combined.
24. 24
    Sift into a bowl, and discard any large pieces of vanilla.
25. 25
    Put the egg whites, vanilla-sugar mixture, and salt in the heatproof bowl of an electric mixer.
26. 26
    Set over a pan of simmering water.
27. 27
    Whisk constantly until the sugar has dissolved and the mixture registers 160F on an instant-read thermometer.
28. 28
    Return the bowl to the mixer; fit the mixer with the whisk attachment.
29. 29
    Beat on medium-high speed until stiff, glossy peaks form and the mixture is cool, about 10 minutes.
30. 30
    Switch to the paddle attachment.
31. 31
    With the mixer on medium speed, add the butter, 1 or 2 tablespoons at a time, mixing well after each addition.
32. 32
    Mix, scraping down the sides of the bowl as needed, until the mixture is smooth.
33. 33
    Mix in the vanilla extract.
34. 34
    Use immediately, or cover and refrigerate.
35. 35
    Put the sugar, egg whites, and salt in the heatproof bowl of an electric mixer.
36. 36
    Set over a pan of simmering water.
37. 37
    Whisk constantly until the sugar has dissolved and the mixture registers 160F on an instant-read thermometer.
38. 38
    Return the bowl to mixer; fit the mixer with the whisk attachment.
39. 39
    Beat on medium-high speed until stiff, glossy peaks form, and the mixture is cool, about 10 minutes.
40. 40
    Switch to the paddle attachment.
41. 41
    With the mixer on medium speed, add the butter, 1 or 2 tablespoons at a time, mixing well after each addition.
42. 42
    Mix, scraping down the sides of the bowl as needed, until the mixture is smooth.
43. 43
    Mix in the chocolate.
44. 44
    Use immediately, or cover and refrigerate.