Preheat oven to 425 degrees.

Line a baking sheet with parchment paper and set aside. Roll the dough out on the baking sheet and set aside.

In a large bowl, combine the apricot and blueberries. Add the sugar, flour, zest and thyme to the fruit and toss to combine thoroughly. Pour the fruit mixture into the center of the dough and fold the sides up over the berries to cover, crimping gently so the dough adheres.

Whisk the egg in a small bowl. Using a pastry brush, coat the edged of the dough with the egg. Sprinkle the dough generously with the sugar.

Bake the crostata for 20-25 minutes or until the dough is golden brown and crisp. Allow the crostata to cool to room temperature before serving.

Cut the crostata into 6 slices and top each slice with whipped cream, if desired. Serve immediately.