In a mixing bowl, combine flour, cocoa powder, sugar, and salt. Cut in butter until the mixture resembles coarse crumbs. Stir in egg yolk and cold water until the dough forms. Wrap in plastic and refrigerate for 30 minutes.

Bake the Crust

Preheat oven to 350°F (175°C). Roll out the chilled dough and fit it into a tart pan. Prick the bottom with a fork and bake for 15-20 minutes or until set. Let cool.

Make the Dark Chocolate Filling

Melt Chocolate

In a saucepan, heat heavy cream until just about to boil. Remove from heat and add chopped dark chocolate. Stir until melted and smooth.

Combine Ingredients

In a bowl, whisk together sugar, vanilla, and eggs. Gradually mix in the chocolate mixture until fully combined.

Bake the Filling

Pour the filling into the cooled tart crust. Bake for 25-30 minutes until the filling is set but still slightly jiggles in the center. Let cool completely.

Prepare the Toppings

Combine Cherries and Sherry

In a small bowl, mix preserved cherries with Pedro Ximénez sherry. Let sit for 10 minutes to absorb the flavors.

Make Coffee Cream

In a mixing bowl, whip heavy cream, espresso, and powdered sugar until soft peaks form.

Assemble the Tart

Top the Tart

Spread the preserved cherries over the top of the cooled chocolate tart. Serve with a dollop of coffee cream on the side.