Step 1Heat the oven to 375 degrees. Spray 2 baking sheets with cooking spray and set aside.
Step 2Pit the cherries, then cut the cherries into quarters. Place the cherries, chocolate, almonds, cardamom, sugar and flour in a bowl and toss gently to combine.
Step 3On a lightly floured work surface, slightly roll out 1 pastry sheet to an 11-inch square. Cut into 9 equal squares with sharp knife. Place 1 tablespoon of filling in the center of each square. Lightly brush the egg wash along the edges of each square, then fold in half to form a triangle and gently press to seal. Dip a fork into the egg wash and press the tines on the pastry edges to help seal. Repeat with the remaining squares and place on the baking sheets. Brush the tops of the turnovers with the egg wash and sprinkle with the crystal sugar. Place the baking sheet in the freezer for 10 minutes while making the second batch of pastries. It is important to freeze the pastries before baking so they'll puff up when baking.
Step 4Bake until golden brown and puffed, 25 minutes. Let cool slightly before serving.