Heat 1 cup of milk in a small saucepan over medium heat until it simmers. Remove from heat and stir in 8 ounces of chopped white chocolate until melted. Mix in 1 tablespoon of instant espresso powder. Let it cool.

In a large bowl, whisk together 2 cups of all-purpose flour, 2 teaspoons of baking powder, and 0.5 teaspoon of salt. Set aside.

Beat 0.5 cup of unsalted butter and 1 cup of granulated sugar until fluffy. Add 3 eggs one at a time and mix in 2 teaspoons of vanilla extract.

Alternately add the flour mixture and 1 cup of milk to the egg mixture, starting and ending with flour. Mix until just combined.

Preheat oven to 350°F (175°C). Divide batter between two greased 9-inch pans and bake for about 40 minutes, or until a toothpick comes out clean.

Let the cakes cool in pans for 10 minutes, then transfer to wire racks to cool completely.

For the buttercream, combine 4 egg whites and 1 cup sugar over simmering water, stirring until warm. Whip until stiff peaks form, then gradually mix in 1.5 cups of unsalted butter and 2 tablespoons of espresso powder.

Once cakes are cool, level the tops if needed. Spread cooled ganache on one layer, then top with the second layer and a crumb coat of buttercream. Chill for 30 minutes.

Reheat remaining ganache to a pourable consistency for drips. Drizzle over top and decorate with sprinkles and coffee beans.