Prepare the Cupcakes:

• Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.
• In a medium bowl, whisk together the flour, baking powder, and salt.
• In a separate bowl, beat the butter and sugar together until light and fluffy. Add the eggs one at a time, beating well after each addition.
• Gradually mix in the dry ingredients alternating with the milk, starting and ending with the dry ingredients.
• Stir in the cooled brewed coffee and vanilla extract.
• Divide the batter evenly between the cupcake liners, filling each about 2/3 full.
• Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean. Allow cupcakes to cool completely.

Make the Mascarpone Filling:

• In a bowl, whisk together mascarpone cheese, heavy cream, powdered sugar, and vanilla extract until smooth and slightly thickened.

Make the Coffee Syrup:

• In a small saucepan, heat the brewed coffee and sugar over medium heat, stirring until the sugar dissolves. Remove from heat and let it cool.

Assemble the Cupcakes:

• Once the cupcakes have cooled, use a small spoon or cupcake corer to remove the center of each cupcake.
• Brush the hollowed-out cupcakes with the coffee syrup to soak them.
• Fill each cupcake with the mascarpone filling.

Topping:

• Dust each filled cupcake with cocoa powder. Optionally, garnish with dark chocolate shavings.

Chill and Serve:

• Place the cupcakes in the refrigerator for about 30 minutes before serving to allow the flavors to meld together.