Position a rack in the lower third of the oven. Preheat the oven to 400┬░F. Have ready an unbuttered 8 x 8-inch baking dish. Prepare:
1/2 recipe Cornmeal Flaky Pastry Dough
On a lightly floured surface, roll out the dough into a 10-inch square, 1/8 inch thick. Transfer to a baking sheet, cover with plastic wrap, and refrigerate while you prepare the filling. Combine:
3 pints blueberries
1/2 cup light brown sugar
2 tablespoons cornstarch or 1/4 cup all-purpose flour
1/4 teaspoon ground cinnamon
1/4 teaspoon salt
Spread the blueberry mixture evenly in the baking pan. Remove the dough from the refrigerator and let stand for a few minutes, until pliable. Fold the dough in half and unfold over the top of the blueberries, covering them. Trim the dough around the pan, leaving a 1/2-inch overhang. Fold the edges of the dough under to fit inside the dish and press the dough gently against the apples (around the edge only). Bake until the top has browned lightly, about 30 minutes. Remove the dish from the oven to a level area. Reduce the oven temperature to 350┬░F. With a knife, score the crust, as you would a pan of brownies, into 2-inch squares. Baste the crust squares by tilting the pan all around and spooning some of the juices over the squares, basting the middle squares as well. You can also submerge the squares in the juices with the back of the spoon. Do not worry about crushing or tearing the crust, for doing this is part of the character of the dish. (The crust will also sink slightly into the juices while cooking.) Return the dish to the oven and bake until the filling has thickened slightly and the crust is golden brown, about 30 minutes more. Let cool for 15 minutes before serving. Serve warm in deep bowls with:
Heavy cream, softly whipped cream, or vanilla yogurt
To store, cover and refrigerate. Reheat, covered with aluminum foil, in a 325┬░F oven for about 20 minutes.
