Preheat your oven to 350°F (175°C).

Steam or cook the broccoli florets until tender, about 5-7 minutes, then drain and set aside.

In a large mixing bowl, combine broccoli, cream of mushroom soup, mayonnaise, cheddar cheese, eggs, and onion. Season with salt and pepper, and mix well.

Grease a 9x13-inch baking dish and pour the broccoli mixture into it, spreading evenly.

In another bowl, combine crushed Ritz crackers with melted butter. Sprinkle this topping over the casserole.

Bake for 30-35 minutes until the topping is golden brown and the casserole is bubbly.

Allow to cool for 5-10 minutes before serving.