Steam the Broccoli lightly don't steam it too long or it will be mushy when baked. You want it to still be lightly crispy. Preheat oven to 350 degrees. Butter or spray a 9x13" baking dish. In a medium bowl, whisk together cream of mushroom soup, mayonnaise, eggs that have been lightly beaten, and onion.
Place broccoli that has been lightly steamed (especially if you are using frozen like I did) in a mixing bowl. Stir in the soup mixture and combine. Stir in the cheese.
Spread mixture into your casserole dish, and sprinkle with pepper and Paprika ( I don't recommend using salt) Place in oven and bake for 45-60 minutes depending on your oven until top has started to brown a little and cheese is melted. I also added a little more cheese to the top before I placed it into the oven. This was so creamy and delicious.