Preheat the oven to Bake at 350°F.
Thoroughly wash the squash and cut off the stem end of the squash so you can see the seeds inside. Scrape out the seeds. This leaves a nice hollow hole for the stuffing.
Sauté the red onion and garlic in a small amount of water.
In a bowl mix cooked quinoa, red onion, garlic, poultry seasoning, chopped sweet red pepper and black pepper.
Stuff the squash with the quinoa mixture and place squash in a casserole dish. If you have any leftover quinoa mixture then put it in the casserole dish beside the squash.
Bake for 30 minutes or until the squash skin is soft.
Remove from the oven, slice the squash in half lengthwise and put each half on a plate.