6cupsblueberriesboth fresh and frozen blueberries will work
3tbspcornstarch
Instructions
Preheat the oven to 350°F, and coat an 8 inch square pan with nonstick cooking spray.
To prepare the topping, whisk together the oats, flour, and cinnamon in a small bowl.
Make a well in the center. Pour in the maple syrup and melted butter. Stir until fully incorporated.
To prepare the filling, toss the blueberries with the cornstarch in a large bowl until completely coated.
Transfer the filling to the prepared pan, and sprinkle evenly with the topping, breaking it up into really small pieces.
Bake at 350°F for 45-55 minutes or until the juice is bubbling at the sides of the pan. Cool completely to room temperature; then refrigerate for at least 3 hours before serving to allow the juices to fully thicken.