Preheat oven to 375°F (190C). Spray an 8-inch square baking dish with cooking spray and set aside.
Rinse blueberries in a colander and set aside to drain.
In a large bowl combine dry muffin mix, oats, and brown sugar. Use a pastry cutter or a fork to cut in the butter until the mixture is crumbly.
Set aside 1 ½ cups of the crumb mixture.
Press the remaining crumb mixture into the bottom of the prepared baking dish to form the crust.
In a small bowl, gently combine drained blueberries, additional fresh berries, and jam. Spoon over the crust and spread evenly.
Sprinkle the remaining crumb mixture over top and gently press down.
Bake for 20-25 minutes, or until golden brown.
Cool completely on a wire rack before cutting into bars.