In a medium saucepan, combine 140 g of white chocolate and 1 1/2 cups of milk. Heat over low heat, stirring gently until melted and smooth, about 5 minutes. Remove from heat and stir in 1 tablespoon of instant espresso powder. Allow to cool.

Preheat oven to 350°F (175°C) and prepare three 6-inch cake pans by greasing and lining with parchment paper.

In a large bowl, whisk together 2 1/2 cups of flour, 2 1/2 teaspoons of baking powder, and 1/2 teaspoon of salt.

In a separate bowl, beat 3/4 cup of unsalted butter and 1 1/2 cups of sugar until fluffy, around 3-4 minutes. Add 3 eggs one at a time, then add 1 teaspoon of vanilla extract.

Gradually mix in the cooled chocolate mixture into the creamed butter and sugar. Alternately mix in the dry ingredients and remaining chocolate mixture until smooth.

Divide the batter between the prepared pans and bake for 35-40 minutes until a toothpick comes out clean. Cool for 10 minutes in pans, then transfer to wire racks.

Create the Espresso Swiss Meringue Buttercream by whisking 3 egg whites and 1 cup of sugar in a heatproof bowl over simmering water until warm and sugar dissolves. Beat until stiff peaks form, around 8 minutes.

Gradually add in 1 1/2 cups of unsalted butter into the meringue. Mix in 1 1/2 tablespoons of instant espresso powder until well incorporated.

Melt 450 g of white chocolate and 150 g of heavy cream in the microwave at 30-second intervals, stirring until silky. Allow to cool slightly.

Once the cakes are completely cool, level the tops if necessary. Place one layer on a plate and spread ganache on top, repeat with the second layer. Apply a crumb coat of ganache around the cake and chill for 30 minutes.

Frost the entire cake with the espresso buttercream and chill for 15-20 minutes to set.

Drizzle ganache around the edges for a drip effect, pipe borders with remaining buttercream, and finish with garnishes. Serve and enjoy!