Rinse squash, cut in half, and scoop out seeds. Cut a small piece off the bottom, if necessary, so that squash doesn't wobble
Place on microwave-safe plate, and cook for 5 to 10 minutes, or until able to pierce with fork. When done, place cut side up on baking sheet, and preheat oven to 400 degrees
Meanwhile, sauté onions in olive oil in a large skillet until translucent. Add diced apples, season with sea salt, garlic powder, pepper and cinnamon, and cook until no longer pink and apples are soft
Stir in dried cranberries and Parmesan cheese, and cook until cheese is melted
Remove from heat. Brush squash with melted butter, and season with a pinch of salt and pepper, if desired. Fill cavities with stuffing
Bake for 20 minutes or until squash is fork tender and stuffing tops are golden brown. If stuffing starts to get too brown, cover loosely with foil until squash is done. Top with more shredded Parmesan, if desired before serving