Preheat your oven to 175°C (347°F) and prepare a muffin pan by lining it with cupcake liners.

In a large mixing bowl, cream together the softened unsalted butter and granulated sugar using an electric mixer on medium speed for about 2-3 minutes.

Gradually add the room-temperature eggs to the butter-sugar mixture, mixing thoroughly after each addition. Then, pour in the pure vanilla extract and blend until everything is smoothly combined.

In a separate bowl, mix the room-temperature whole milk with freshly brewed coffee until combined. Slowly pour this mixture into the batter while mixing on low speed.

In another bowl, sift together the all-purpose flour, baking powder, and salt. Gently fold this dry mixture into the wet batter using a spatula.

In a small bowl, mix the baking soda and white vinegar. Quickly add this mixture to your batter and fold gently until just combined.

Fill each cupcake liner about ¾ full with the batter and place the pan in the preheated oven. Bake for 20-22 minutes or until a toothpick inserted in the center comes out clean.

Once baked, remove the pan from the oven and let the cupcakes cool in the pan for about 5 minutes. Then, transfer them to a wire rack to cool completely.

In a clean bowl, beat the softened butter until it's light and creamy. Gradually add the sifted powdered sugar, mixing on low until incorporated.

Dissolve the espresso powder in the heavy cream, then gradually add this to the buttercream while beating it on medium speed.

Once the cupcakes are completely cool, generously frost each one with the creamy coffee buttercream. Enjoy!