Preheat the Oven:
Set your oven to 350°F (175°C). Grease a 9×13 inch casserole dish with the tablespoon of butter to prevent sticking.

Prepare the Base Mixture:
In a large bowl, combine the cream of chicken soup, cream of mushroom soup, water, and uncooked instant rice. Stir well until evenly mixed.

Pour into the Baking Dish:
Transfer the soup and rice mixture into the greased casserole dish and spread evenly.

Add Optional Ingredients (If Using):
Stir in frozen vegetables or shredded cheese if desired. These add-ins can elevate the dish and make it more substantial.

Top with Chicken:
Place the raw chicken breasts directly on top of the rice mixture. If they’re particularly thick, consider butterflying them for even cooking.

Sprinkle Soup Mix:
Evenly sprinkle the onion soup mix over the top of the chicken. This adds both seasoning and savory depth.

Cover and Bake:
Cover the dish tightly with aluminum foil and bake for 60 minutes. Do not lift the foil during baking—this traps the moisture and ensures the rice cooks evenly.

Check for Doneness:
After 1 hour, remove the foil. The chicken should be fully cooked (internal temperature of 165°F/75°C), and the rice should be tender and creamy.

Optional Broil:
For a golden top, broil the casserole uncovered for 3–5 minutes until lightly browned.

Let Rest and Serve:
Allow to rest for 5–10 minutes before serving. This gives the casserole time to set and makes it easier to serve.