Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a mixing bowl, combine flour and cold butter. Use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs.
Gradually add ice water, mixing until the dough comes together. Form into a disk, wrap in plastic, and refrigerate for 30 minutes.
In another bowl, combine cherries, sugar, cornstarch, and almond extract. Set aside.
Roll out the dough on a floured surface into a 12-inch circle. Transfer to the prepared baking sheet.
Place the cherry mixture in the center of the dough, leaving a 2-inch border. Fold the edges of the dough over the filling, pleating as you go.
Brush the dough with beaten egg and sprinkle with sliced almonds.
Bake for 35-40 minutes, or until the crust is golden and the filling is bubbly. Let cool before serving.