Take the dough circle out of the freezer and let thaw for 15 minutes on a piece of parchment paper on a baking sheet. Set aside.
Meanwhile, in a large bowl combine the blueberries, sugar, cornstarch, salt, crystalized ginger, and lemon juice. Mix well to combine.
In a small bowl combine the flour, oats, sugar, and salt and mix well. Cut the butter into small pieces and place in the bowl. Use your fingers and mix together until a crumble forms.
Spoon the blueberry mixture into the center of the dough circle, leaving 1 1/2 inches around the edges. If there is extra liquid in the bowl from the blueberries discard it instead of pouring it onto the dough circle.
Sprinkle the blueberry mixture with the crumble topping.
Carefully fold up the 1 1/2 inch border of the dough circle up over top of part of the blueberry filling. Use a fork to press the edges to seal them.
Bake for 30 minutes. If the top of the dough is getting too brown cover with a piece of foil and continuing baking for an additional 15 minutes.
Remove from the oven and cool on a wire cooling rack for at least 30 minutes before cutting and serving.