In a large bowl, mix together the mayo, cream of mushroom soup, eggs (beaten), shredded cheese, onion and broccoli. The broccoli will still be frozen when you mix it together as seen in the process photos.

Spray the 9x11 casserole dish with non stick cooking spray. Pour the mixture in the casserole dish.

Put about 2 or 3 cups of cheese crackers in a large baggy and use a rolling pin to crush the crackers. This will be the crust for the top of the casserole.

Sprinkle the crumbled cheese cracker topping over the top of the uncooked casserole.

Put small pats of butter over the cracker topping. I used very thin slices of real butter.

Bake at 375 degrees for 45 minutes.