Melt the butter in a sauté pan and add the squash and onion. Season with salt and pepper.
Saute over medium heat until the squash begins to brown.
Put the squash and onions into a bowl and add the Velveeta cubes.
Then add ⅔ of the cracker crumbs and the egg. Mix thoroughly.
Put squash mixture into a casserole dish, sprinkle with remaining cracker crumbs, and bake for 30 minutes at 350 degrees.
