01 -
Combine heavy cream and chopped chocolate in a microwave-safe bowl. Heat in 15-20 second intervals, stirring between each, until the mixture is warm and chocolate is nearly melted. Allow residual heat to finish melting, microwaving for another 10-15 seconds only if needed. Avoid overheating. Cover with a plate and rest at room temperature for 90 to 120 minutes, stirring every 30 minutes, until thickened and spreadable.
02 -
Preheat oven to 350°F. Line two 8-inch or 9-inch round pans with parchment paper and grease with butter or oil.
03 -
If making buttermilk, combine 1 cup whole milk with 1 tablespoon vinegar or lemon juice. Stir and set aside for at least 5 minutes.
04 -
In a large bowl, whisk together flour, granulated sugar, baking powder, baking soda, and salt until homogenous. Sift flour for a smoother batter.
05 -
Add eggs, vegetable oil, and buttermilk to the dry mixture. Gently whisk until combined and no dry spots remain. Do not overmix.
06 -
In a separate bowl, whisk boiling water with cocoa powder and instant coffee until smooth and glossy.
07 -
Fold the bloomed cocoa and coffee mixture into the cake batter until just combined. The batter will be loose.
08 -
Pour batter evenly into prepared pans. Bake for 20-25 minutes (9-inch pans) or 23-28 minutes (8-inch pans), until a toothpick inserted in the center emerges with moist crumbs.
09 -
Let cakes rest in pans for 10-15 minutes. Carefully turn out onto a wire rack to cool completely before frosting.
10 -
Using a serrated knife, level the cake tops. Place one layer on a serving stand, spread one-third of ganache over it. Position the second layer on top and cover cake with remaining ganache, using an offset spatula to finish. To prevent crumbs, apply a thin crumb coat and chill 15 minutes before final frosting.