Preheat your oven to 350°F (175°C) and lightly grease an 8x8 baking dish with olive oil or nonstick spray.

In a large skillet, melt 2 tablespoons of unsalted butter over medium heat. Add diced chicken and chopped onion, and sauté until chicken is browned and onion is translucent, about 6-8 minutes.

Tip: If using a meat thermometer, cook chicken to 150°F, it will reach 165°F during baking.

Choose to roast or blanch the broccoli. For roasting, toss florets with olive oil and roast at 400°F for 12-15 minutes. For blanching, add to boiling water for 2-3 minutes, then plunge into ice water.

Tip: If using frozen broccoli, thaw and pat dry.

In a large bowl, whisk together beaten eggs and milk. Add cooked rice, 1 cup of cheese, and prepared broccoli. Season lightly with black pepper and garlic powder.

Pour rice-broccoli mixture into the baking dish, spreading evenly. Top with browned chicken and onions.

Bake uncovered in the oven for 45 minutes.

Sprinkle remaining cheese on top and bake for an additional 15 minutes until cheese is melted and bubbly.

Let the casserole rest for 5-10 minutes before cutting.