01 -
Preheat oven to 350°F. Spray two 9-inch round baking pans with non-stick spray. Line bottoms with parchment paper rounds and spray again
02 -
In a large bowl, sift together flour, cocoa powder, baking soda, baking powder, and salt; set aside
03 -
Beat butter until smooth, about 1 minute. Gradually add both sugars and beat until light and fluffy, about 4 minutes
04 -
Add eggs and egg yolk one at a time, beating well after each addition. Add vanilla extract and beat until combined
05 -
In a measuring cup, combine oil and sour cream
06 -
On lowest speed, add flour mixture in three additions, alternating with sour cream mixture in two additions, mixing until just combined
07 -
Pour in hot coffee, let sit 30 seconds, then gently stir with rubber spatula until evenly combined
08 -
Divide batter between pans (about 850 grams per pan) and smooth tops. Bake for 38-45 minutes until toothpick inserted comes out clean or with few moist crumbs
09 -
Cool cakes in pans on wire rack for 20 minutes, then invert onto rack to cool completely, about 1 hour
10 -
Finely chop chocolate and place in bowl of stand mixer with whisk attachment
11 -
Heat cream and corn syrup until just short of boiling. Pour over chopped chocolate and let sit 2 minutes
12 -
Gently stir until chocolate is melted and mixture is smooth and glossy. Stir in vanilla
13 -
Beat in butter 1 tablespoon at a time, ensuring each addition is incorporated before adding more. Beat in salt
14 -
Refrigerate frosting, loosely covered, for about 1 hour until firm enough to spread
15 -
Trim domed tops of cakes, then slice each cake in half horizontally to create 4 even layers. Save trimmings for decoration
16 -
Place one layer on cake stand. Spread 1/2 cup frosting on top, add next layer, and repeat until all layers are stacked
17 -
Spread remaining frosting over top and sides of cake
18 -
Crumble reserved cake scraps and gently press around sides of cake
19 -
Allow cake to set for 20 minutes before slicing. Store in refrigerator up to 5 days, bringing to room temperature before serving