First, get your oven warmed to 175°C (350°F) and line your cupcake pan with liners, whether you go fancy or simple, it’s up to you!
In a large bowl, combine the softened salted butter with both the granulated and light brown sugars. Beat these together until the mixture looks light, fluffy, and just a bit dreamy.
Next, crack the eggs in one at a time, mixing well after each addition to keep the batter silky smooth. Add the vanilla extract to bring that warm, comforting flavor.
In a separate cup, mix your whole milk with the freshly brewed coffee (make sure the coffee is cooled!). Slowly pour this liquid into the batter while mixing on low speed, blending everything together nicely.
Now it’s time for the dry stuff, sift your flour, baking powder, and baking soda over the wet ingredients. Gently fold everything together using a spatula.
Fill each cupcake liner about ¾ full to leave room for a perfect rise. Pop them into the oven and bake for about 18 to 20 minutes. Let them cool completely on a wire rack before frosting.
To make the frosting, whip cold mascarpone and heavy cream until thick, fluffy peaks form. Stir in the instant espresso powder and sifted powdered sugar carefully, folding until everything’s smooth and creamy.
Finally, pipe or spread that luscious frosting on your cooled cupcakes. Add a generous dusting of cocoa powder on top, then enjoy every bite!