Italian Fruit Crostata (Blueberry)

Preheat oven to 450F. Prepare a half-sheet size sheet pan with parchment paper. Lay out the refrigerated pie crust onto the baking sheet and set aside. For the filling, gently stir together the berries, lemon juice, zest, sugar, and cornstarch in a bowl. For the Assembly: In a small bowl, lightly beat the egg. Spoon the filling onto the center of the dough, leaving a 2-3 inch border uncovered around the edge. Fold the edge up and over the filling, forming loose pleats and pinch. Brush pastry with egg wash and sprinkle crust with sugar if desired. Dot the top of the galette with the pea-sized butter pieces. Bake until the filling is bubbling and the pastry is golden brown, about 25 minutes. Cut into wedges and serve with ice cream if desired. ENJOY!!!!