Method
Preparation
Preheat your oven to 350°F (175°C).
Combine flour, cocoa powder, powdered sugar, and salt in a bowl.
Add chilled butter, mixing until coarse crumbs form.
Stir in egg yolk and cold water until dough clumps together.
Press dough into a tart pan, prick with a fork, and bake for 15-20 minutes.
Let the crust cool completely.
Filling and Assembly
Whip heavy cream until soft peaks form.
Combine mascarpone, powdered sugar, cooled espresso, vanilla, and coffee liqueur until smooth.
Fold whipped cream into mascarpone mixture gently.
Pour filling into cooled tart crust and smooth the top.
Refrigerate for at least 2 hours to set.
Dust with cocoa powder and add chocolate shavings and coffee beans, if desired.
Slice and serve chilled.
Notes
For a creamier filling, incorporate mascarpone cheese at room temperature. Remember to chill the tart for at least 2 hours for best results.