Preheat oven to 350°F. Grease a 13x9 inch baking dish.

Place broccoli in a large microwave-safe bowl. Pour ¼ cup water into the bottom, cover, and microwave on high for 4–5 minutes. The broccoli should be completely defrosted.

Drain the broccoli well.

Place 4 tablespoons of butter in a large skillet. Add the onion and cook for 4–5 minutes, or until the onion is very soft. Sprinkle in the flour and cook for 1 minute, stirring frequently.

Whisk in the milk and salt. Cook for 2 minutes, or until thickened slightly. Stir in the Velveeta and cook until the Velveeta is melted and the mixture is smooth.

Add the broccoli and beaten eggs to the Velveeta mixture. Stir to combine.

Pour into the prepared dish.

Melt the remaining 4 tablespoons butter. Place in a medium bowl, and stir in the crushed Ritz crackers. Sprinkle the mixture over the broccoli in the casserole dish.