Preheat your oven to 350°F (175°C). Grease two 9-inch round cake pans, line the bottoms with parchment paper, then grease the paper.
In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt until well combined.
2 cups all-purpose flour, 2 cups granulated sugar, 3/4 cup unsweetened cocoa powder, 2 teaspoons baking soda, 1 teaspoon baking powder, 1 teaspoon salt
In another bowl, beat eggs, buttermilk, oil, and vanilla extract until smooth.
2 large eggs, 1 cup buttermilk, 1/2 cup vegetable oil, 2 teaspoons pure vanilla extract
Gradually add the wet ingredients to the dry ingredients, mixing on medium speed until just combined. Avoid overmixing.
Slowly pour in the hot coffee (or hot water) and mix on low speed until the batter is smooth.
1 cup hot coffee
Divide the batter evenly between the prepared cake pans.
Bake for 30-35 minutes, or until a wooden skewer inserted in the center comes out clean or with few moist crumbs.
Let the cakes cool in the pans for 10 minutes, then invert them onto a cooling rack to cool completely.
Beat softened butter until creamy. Gradually add cocoa powder, then alternately add powdered sugar and milk, beating on medium speed until smooth and creamy. Beat in vanilla extract, salt, and melted chocolate until well combined and fluffy.
1 1/2 cups unsalted butter, 1 cup unsweetened cocoa powder, 5 cups powdered sugar, 1/2 cup whole milk, 2 teaspoons pure vanilla extract, 1/4 teaspoon salt, 8 oz semi-sweet chocolate chips, Fresh berries
Level the cakes if needed using a serrated knife. Place one cake layer on a serving plate, spread about 1 cup of frosting evenly over the top. Add the second cake layer. Apply a thin crumb coat over the entire cake and refrigerate for 15 minutes. Then apply the remaining frosting generously and decorate with optional toppings.
Fondant decorations, Birthday cake topper, Sprinkles or edible gold flakes