Prepare the Whipped Coffee Ganache (Day Before)

1. Finely chop the white chocolate and melt it gently in the microwave in short intervals or over a double boiler until smooth.
2. Heat 187 g of heavy cream with the instant espresso powder in a saucepan, stirring until the coffee dissolves and the cream begins to simmer.
3. Gradually pour the hot coffee cream over the melted white chocolate, stirring from the center until smooth and glossy.
4. Add the remaining 187 g of cold heavy cream and blend with an immersion blender until completely smooth.
5. Cover with plastic wrap touching the surface and refrigerate for at least 6 hours, preferably overnight.

Make the Chocolate Espresso Cupcakes

1. Preheat the oven to 350°F (180°C) and line a muffin pan with cupcake liners.
2. Dissolve the instant espresso powder in the hot water and let cool slightly.
3. Beat the softened butter and granulated sugar for 2–3 minutes until light and fluffy.
4. Add the eggs one at a time, mixing after each addition, then mix in the vanilla extract and dissolved espresso.
5. In a separate bowl, whisk together the cake flour, cocoa powder, baking powder, baking soda, and salt.
6. Add the dry ingredients in three additions, alternating with the buttermilk in two additions. Mix on low speed just until combined.
7. Divide the batter evenly between the cupcake liners, filling each about ⅔ full.
8. Bake for approximately 20 minutes, until a toothpick inserted into the center comes out clean or with a few moist crumbs.
9. Let the cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Whip the Ganache and Decorate

1. Beat the chilled ganache on medium-low speed until thick, fluffy, and firm enough to hold its shape while remaining smooth and creamy. Stop immediately to avoid overwhipping.
2. Transfer the whipped coffee ganache to a piping bag fitted with a large star tip.
3. Pipe generous swirls onto the completely cooled cupcakes.

Chocolate drizzle

1. Heat the heavy cream until just simmering, then pour it over the chopped chocolate.
2. Let sit for 1 minute, then stir until smooth and glossy.
3. Let cool slightly before drizzling over the frosted mocha cupcakes.