In a large bowl, combine ground beef, uncooked rice, salt, pepper, and grated onion.

Mix the ingredients thoroughly until well combined.

Form the mixture into small, evenly sized meatballs.

Spray a large glass baking dish with cooking spray (Pam).

Place the meatballs in the prepared baking dish.

In a saucepan, combine tomato soup, water, and ketchup.

Heat the sauce mixture to a boil, stirring occasionally.

Carefully pour the boiling sauce over the meatballs in the baking dish.

Cover the dish with a glass lid or aluminum foil.

Bake in a preheated oven at 350°F (175°C) for 1 to 1 1/2 hours, or until the rice is fully cooked and tender.