Preheat oven to 375. Roll out dough on a lightly floured work surface to roughly an 11-inch circle. Transfer the dough to a parchment-lined baking sheet. Mix the pitted cherries with 1/4 cup sugar, salt, and liqueur.
Spoon the seasoned cherries over the dough and leave a 2-inch border. Drop pieces of butter over the cherries and fold the edges of the dough over, pressing lightly.
Whisk the cream or milk and the egg yolk together and lightly brush the edges of the crust.
Sprinkle with the remaining tablespoon of sugar and then bake for 40-45 minutes. Ovens will vary, bake until golden.
Top each serving with a dollop of mascarpone and a sprinkle of black pepper.