Preheat your oven to 375°F (190°C) and lightly grease a baking dish (9×13-inch).
Heat the olive oil in a large skillet over medium heat.
Add the diced onion and cook for about 3–4 minutes, until soft.
Add the ground beef and cook until fully browned, breaking it up as it cooks.
Drain excess fat if needed.
Stir in the garlic, salt, pepper, paprika, and Italian seasoning.
Cook for 30 seconds until fragrant.
In a large bowl, whisk together the beef broth, milk, and cream of mushroom soup.
Add the uncooked rice and cooked beef mixture to the bowl.
Stir well so the rice is evenly coated.
Transfer the mixture into the prepared baking dish and spread evenly.
Cover tightly with foil and bake for 35 minutes.
Remove the foil, sprinkle the cheddar and mozzarella evenly over the top, and return to the oven uncovered.
Bake for another 10–15 minutes, until the cheese is melted and the rice is tender.
Let the casserole rest for 5 minutes before serving.
Garnish with parsley if desired.
