Preheat oven to 350°F. Grease a 9x13-inch pan. Prepare Rice-A-Roni according to boxed directions.
While rice is cooking, cook ground beef in a skillet over medium heat until no longer pink. Drain fat.
In a mixing bowl, combine cooked beef, prepared rice, and soup. Spread into prepared pan. Top rice mixture with shredded cheddar cheese and fried onions.
Bake in oven for about 20 minutes. Remove and serve.
Notes
Refrigerate leftovers in an airtight container for up to 3 days; reheat in the microwave. Can be frozen unbaked (thaw completely before baking) or baked and frozen for up to 3 months. Can be assembled up to 24 hours ahead and refrigerated before baking; add extra bake time if going in cold. Ground turkey can replace ground beef, and cream of celery or mushroom soup can replace cream of chicken.