1 1/2 cup unsalted butter
7 cups sifted powdered sugar
1 1/2 teaspoon vanilla extract
2 pinches of fine sea salt
2 Tablespoons whole milk
food gel colors, as needed
Chocolate Cake :
Preheat the oven to 350 degrees F. Line three 6-inch round cake pans with parchment paper. Lightly grease and set aside.
Whisk together flour, cocoa powder, espresso powder, baking powder, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, mix together coconut oil, sugar, eggs, and vanilla until combined. On low speed, alternate adding the dry flour mixture and milk. Add about 1/3 of the flour mixture, followed by half of the milk. Add another 1/3 of flour, followed by the remaining half of milk. Scrape down the bowl as needed to ensure thorough mixing. Add sour cream and remaining flour. Mix until combined and there are no longer any dry streaks of flour.
Divide batter among prepared cake pans. Level batter. Bake for 25-28 minutes until a toothpick inserted in the center of the cake comes out clean. Allow cake to cool in pan for 5 minutes before unmolding. Allow cakes to cool to room temperature on a wire rack.
In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), cream together butter, powdered sugar, vanilla, and salt. Beat until smooth. Add milk to adjust consistency.