1/3 cup vegetable oil
3 large eggs, at room temperature
1 tablespoon red food coloring
2 teaspoons apple cider vinegar
1 teaspoon vanilla extract
1 cup buttermilk
12 tablespoons (1½ sticks) unsalted butter, softened, plus more for the pans
3 cups cake flour (sift before measuring)
3 tablespoons unsweetened Dutch-process cocoa powder
1 teaspoon baking soda
½ teaspoon salt
1¾ cups granulated sugar
2 pounds (about 8 cups) confectioners sugar
1 tablespoon fresh lemon juice
½ teaspoon vanilla extract
⅛ teaspoon salt
4 8-ounce packages cream cheese, softened
2 sticks unsalted butter, softened
1. Make the cake: Preheat the oven to 350°, Butter two 9-inch-round cake pans and line the bottoms with parchment paper; butter the parchment Whisk the flour, cocoa powder. baking soda and salt in a bowl.
2. Beat the granulated sugar. 12 tablespoons butter and the vegetable oil in a stand mixer fitted with the paddle attachment on medium high speed until fluffy, about 4 minutes. Beat in the eggs one at a time. Beat in the food coloring. vinegar and vanilla. Reduce the mixer speed to low; add the flour mixture in 3 batches. alternating with the buttermilk, beginning and ending with the flour. until just combined.
3. Divide the batter between the prepared pans. Bake until a toothpick inserted into the center comes out clean. 35 to 40 minutes. Let cool 10 minutes on racks. then turn the cakes out onto the racks to cool completely. Using a long serrated knife, carefully slice each cake in half horizontally to make 2 even layers.
4. Make the frosting: Beat the cream cheese and butter in a stand mixer with the paddle attachment on medium-high speed until fluffy. Add the confectioners’ sugar. lemon juice. vanilla and salt; beat until smooth.
5. Put 1 cake layer on a platter; spread 1¼ cups frosting on top. Repeat to make 4 layers. ending with the cake. Cover the top and sides with a thin layer of frosting (this is the “crumb coat”; it doesn’t have to be perfect). Chill 15 minutes. then cover with the remaining frosting.