Slice squash about 1/4-inch thick; cook in boiling salted water until tender.

Fry bacon until crisp; drain on paper towels. Crumble bacon and set aside.

In bacon drippings, brown onions. Add butter, squash, eggs, salt and pepper. Cook, stirring, until eggs are cooked.

In a 2-quart casserole dish, place half of the squash mixture. Sprinkle with half of the crumbled bacon and half of the shredded cheese. Top with remaining squash mixture, then bacon and cheese.

Bake at 350° until hot and cheese is melted.