Preheat oven to 350 degrees F.
Cut squash in half lengthwise and remove fibers and seeds; discard. Score the insides of each half several times with a sharp knife.
In a medium bowl, mix together blueberries, diced apple, brown sugar, and butter. Fill squash halves with blueberry mixture.
Place in an ungreased casserole dish, cut side up. Add about approximately 1/4-inch of water to the bottom of the baking pan so that the skins don't burn and the squash doesn't get dried out.
Cover pan with aluminum foil and bake 50 to 60 minutes. Remove cover and bake another 10 minutes or until squash is tender when flesh is poked with a fork.
Remove from oven and serve immediately.
Makes 6 Servings.
Baked Squash with Blueberries Recipe: https://whatscookingamerica.net/vegetables/bluesquash.htm