Preheat your oven to 350 degrees F. Coat a 9-inch x 13-inch baking dish with non-stick cooking spray.
Spread 32 ounces frozen blueberries evenly in the dish. Drizzle all over with 4 tablespoons maple syrup and sprinkle with 1 1/2 tablespoons ground cinnamon.
Sprinkle 15.25 ounces white cake mix over the blueberries in an even layer.
In a small mixing bowl, whisk together 1 cup half and half and melted 1/2 cup salted butter. Drizzle the mixture all over the cake mix. Use a rubber spatula to gently spread the liquid over the cake mix.
It's okay if there are dry patches, you're not making a dough.
Bake for 35-45 minutes or until the top is golden brown and the blueberries are bubbling.
Remove from the oven and allow to cool 10-15 minutes before serving warm topped with vanilla ice cream, if desired.
Notes
If you don't have salted butter on hand, add 1/4 teaspoon salt to the cake mix before sprinkling it over the berries.