In a medium saucepan over low heat, combine the milk and white chocolate, stirring constantly until melted and smooth, about 5 minutes. Whisk in the instant espresso powder until dissolved, then remove from heat and let cool.

Preheat your oven to 350°F (175°C) and prepare three 6-inch round cake pans by greasing them lightly.

In a large mixing bowl, sift together the all-purpose flour, baking powder, and salt. Whisk until combined.

In a stand mixer, beat the unsalted butter and granulated sugar on medium speed for 4–5 minutes. Add the eggs one by one, mixing well after each addition, then add the vanilla extract.

Gradually incorporate the dry ingredients into the butter mixture, alternating with the cooled white chocolate mixture, until just combined.

Divide the batter evenly among the prepared cake pans. Bake for about 40 minutes, or until a toothpick comes out clean. Allow to cool in pans for 10 minutes before transferring to wire racks.

To make the Swiss meringue buttercream, combine egg whites and sugar in a heatproof bowl over a double boiler and whisk until warm. Beat until stiff peaks form, then gradually add softened butter and the remaining espresso powder.

For the ganache, combine chopped white chocolate and heavy cream in a microwave-safe bowl. Microwave at medium power in 30-second intervals, stirring until melted and smooth.

Once all components are cool, place one cake layer on a serving platter, spread with a layer of ganache, add a second layer, repeating the process.

Drizzle the ganache over the top of the cake, chill for 30 minutes to set the ganache, then decorate with remaining buttercream, coffee beans, and chocolate crispearls.