Preheat your oven to 350°F (180°C) and prepare three 6-inch round cake pans with non-stick spray and parchment paper.

In a large mixing bowl, combine 2 cups of all-purpose flour, 2 teaspoons of baking powder, ½ teaspoon of baking soda, and ½ teaspoon of salt; whisk together and set aside.

Cream 1 cup of unsalted butter with 1 ¾ cups of granulated sugar until light and fluffy, about 3-5 minutes. Then beat in 4 eggs one at a time, followed by 2 teaspoons of vanilla extract and 2 tablespoons of instant coffee dissolved in 1 tablespoon of hot water.

Gradually add the dry mixture to the wet, alternating with 1 cup of buttermilk until all are combined, being careful not to overmix.

Pour the batter into the prepared pans and bake for 27-31 minutes or until a toothpick comes out clean.

Allow cakes to cool in the pans for 2 minutes, then transfer to a wire rack to cool completely.

For frosting, beat 1 cup of softened unsalted butter until fluffy. Gradually add 4 cups of powdered sugar, then incorporate 2 tablespoons of dissolved coffee and 1 teaspoon of vanilla extract.

To prepare the ganache, heat ½ cup of heavy cream until simmering, remove from heat, and add 5 ounces of chopped white chocolate. Stir until smooth and let cool slightly.

Once cooled, stack cake layers with buttercream in between. Apply a crumb coat and chill for 30 minutes.

Frost the cake with a final layer of buttercream, pour the ganache over the top and let it drip down the sides.

Decorate with remaining buttercream and garnish with cocoa powder or espresso beans.

Slice and serve alongside coffee or espresso.