In a small saucepan, combine coffee and sugar. Heat over medium heat, stirring until sugar is dissolved.
Remove from heat and stir in coffee liqueur, if using.
Let cool slightly.
Make the Mascarpone Frosting:
In a large bowl, beat mascarpone cheese until smooth.
In a separate bowl, beat heavy cream until stiff peaks form.
Gradually add powdered sugar and vanilla extract to the whipped cream, and beat until combined.
Gently fold the mascarpone cheese into the whipped cream mixture until smooth.
Assemble the Cupcakes:
Once cupcakes are completely cool, poke holes in the top of each cupcake with a skewer or fork.
Brush or drizzle coffee syrup over the top of each cupcake, allowing it to soak in.
Frost the cupcakes with mascarpone frosting.
Dust with cocoa powder.
Refrigerate for at least 30 minutes before serving to allow the flavors to meld.
Enjoy your Tiramisu Cupcakes!
