Heat 2 tablespoons butter in a large skillet. Brown squash on both sides. Place in a 2 quart casserole. Add another tablespoon of butter to skillet and cook onions until golden brown. Place in casserole.

Combine beef, bread crumbs, 1/2 teaspoon salt, pepper and milk. Shape into 16-18 balls.

Melt remaining butter in skillet and brown meatballs on all sides. Add to vegetables. Sprinkle with salt and mix lightly. Add the soup and bake covered 1 hour at 350 degrees. Serves 4-6.