In a large skillet over medium-high heat, melt 2 tablespoons of butter.
Add the chopped zucchini and onion powder. Stir occasionally and cook for about 10 to 12 minutes, until the zucchini is crisp and tender.
Transfer the zucchini mixture to a bowl and let it cool slightly.
In a microwave-safe bowl, melt the remaining 2 tablespoons of butter. Drizzle it over the crushed Rice Chex, tossing to coat evenly.
In the bowl with the cooled zucchini, mix in the shredded cheese, slightly beaten eggs, salt, and pepper. Stir until well combined.
Grease an 8-inch square baking dish and pour the zucchini mixture into the dish, spreading it evenly.
Sprinkle the buttered Rice Chex mixture over the top of the casserole.
Preheat your oven to 350 degrees Fahrenheit. Bake the casserole, uncovered, for 25 to 30 minutes.
Remove the casserole from the oven and let it cool for about 10 minutes before serving.
Serve warm and enjoy!
