Preheat oven to 350 degrees F.
Sauté the squash in olive oil over medium-low heat until the squash is soft, about 15 to 20 minutes.
Line a colander with a clean tea towel. Place the cooked squash in the lined colander. Squeeze excess moisture from the squash. Set aside.
In a medium size skillet, sauté the onion in butter for 5 minutes.
Remove from pan and mix all ingredients together except cracker crumbs.
Pour mixture into a buttered casserole dish and top with cracker crumbs. Bake for 25 to 30 minutes.