Lightly spray a 12-cup muffin pan with baking spray with flour.
Cut one-third of Shortcrust Dough (about 280 grams); rewrap, and refrigerate until ready to use. On a lightly floured surface, roll remaining two-thirds of dough (about 560 grams) to ⅛-inch thickness. Using a 4-inch round cutter, cut 12 circles from dough. Cut a 2-inch slit in each circle from center toward edge. (This will help get the circles in the pan.) Press each circle into prepared cup, allowing dough to overlap as needed to fit without stretching or tearing. Lightly press dough, especially at overlap, to create uniform thickness and leave a ⅛-inch overhang just over each cup. Refrigerate for at least 30 minutes or until ready to use.
In a medium saucepan, combine cherries, granulated sugar, cornstarch, salt, and extracts. Bring to a boil over medium heat; cook, stirring frequently, until thickened and sauce is translucent, 10 to 15 minutes. Remove from heat, and let cool completely.
In a small bowl, whisk together egg and 1 tablespoon (15 grams) water.
Remove remaining Shortcrust Dough from refigerator; on a lightly floured surface, roll to ⅛-inch thickness. Using a 3-inch round cutter, cut 12 circles. Using a small cutter or round piping tip, cut a small circle from center of each 3-inch circle.
Spoon 3 tablespoons (65 grams) filling into each prepared crust in cups. Using a pastry brush, lightly brush egg wash along edge of each cup. Place a 3-inch circle on each muffin cup, pressing along excess bottom dough to seal; using 3-inch round cutter, cut off excess. Refrigerate until firm, at least 15 to 20 minutes.
Preheat oven to 350°F (180°C).
Lightly brush tops of pies with egg wash.
Bake until golden brown, 35 to 40 minutes. Let cool in pan for 15 to 20 minutes. Using a thin-bladed knife or offset spatula, run blade around top edge of each cup. Using knife to help lift, remove pies from pan, and let cool completely on a wire rack. When ready to serve, garnish with confectioners’ sugar, if desired. Refrigerate in a airtight container for up to 3 days.