1. Preheat oven to 350F. Grease a 9 x 13-inch
baking pan. Add 3 cups of blueberries to the
pan, spreading evenly across. Sprinkle
cornstarch evenly across. Sprinkle sugar evenly
across.
2. Sprinkle cake mix on top of blueberries, trying
to spread evenly across. Spread butter chunks
evenly on top. Sprinkle the remaining 1 cup of
blueberries on top.
3. Bake for 45-55 minutes or until the cake mix is
golden brown and no raw cake mix remains. Let the cake cool for about 30 minutes before serving
and eating.
