Prepare Baking Pans: Preheat your oven to 350°F (175°C). Grease three 9-inch round cake pans and line the bottoms with parchment paper.

Mix Dry Ingredients: In a large bowl, whisk together the all-purpose flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt.

Combine Wet Ingredients: In another bowl, mix the buttermilk, sour cream, vegetable oil, eggs, and espresso powder until smooth.

Combine Everything: Slowly add the wet mixture into the dry ingredients, mixing gently. Then add the hot water or coffee to the batter.

Bake: Divide the batter among the pans and bake for 25-30 minutes, or until a toothpick comes out clean.

Cool: Let the cakes cool in the pans for about 10 minutes, then cool completely on wire racks.

Make Ganache: Heat the heavy cream until simmering and pour it over the chopped white chocolate, stirring until smooth.

Prepare Frosting: Beat the softened butter until creamy, gradually add cocoa powder and powdered sugar, and mix with milk for consistency.

Assemble Cake: Place one layer on a plate, spread ganache, add the second layer, repeat, and cover the whole cake with dark chocolate frosting.

Serve: Garnish with fresh raspberries or mint leaves, slice, and enjoy!