Place the squash face up in a baking pan, and brush the squash with olive oil
Sprinkle garlic powder, sea salt and pepper (omit if AIP) on the squash and bake for 40 minutes or until tender with a fork
While the squash is baking, cook the ground beef/turkey on medium heat in a frying pan. Optional: cook the meat and veggies in broth for more flavor.
Add a dash of garlic powder, sea salt, and pepper (omit if AIP) to the meat
When the the ground beef/turkey is done cooking, transfer it to a large bowl
Leave a small amount of the drippings in the frying pan, and cook the onion, celery, and green pepper (omit if AIP) for about 5 minutes
Add the diced apple to the frying pan, and cook another 3-4 minutes
Once the veggies are tender (~8-10 minutes), let them cool, and transfer them to the bowl with the ground meat
Mix the meat and veggies together, and taste. You may choose to season it with more salt, pepper, and/or garlic powder. Some like a 1/4 tsp of sage. Others prefer a dash of cinnamon and nutmeg.
When the seasonings are to your liking, beat an egg if using (omit if AIP), and combine the whole mixture
Stuff your peppers with the meat and veggie mixture, and bake another 15-20 minutes, or until the edges are golden brown
If there is extra meat/veggie mixture, cook it in a ramekin for the same 15-20 minutes