Cook squash in salted boiling water until tender. Drain well; press as much water out of the squash as possible. Set aside.
Preheat oven to 350º F.
Cook bacon until crisp; drain well, reserving 1 Tablespoon of the drippings. Sauté the onion in the reserved drippings. Add squash, cheese, salt and pepper; mixing well. Spoon into a greased casserole. Bale at 350º F for 30 minutes, or until bubbly and nicely browned. Yield: 6 to 8 servings.