Preheat oven to 375°F (190°C) and lightly grease a baking dish.
Heat olive oil in a skillet over medium heat. Sauté onions and mushrooms for 5–6 minutes until softened.
Add garlic and cook for 30 seconds until fragrant.
Stir in heavy cream, Italian seasoning, salt, and pepper. Simmer for 2–3 minutes.
In the prepared baking dish, spread the cooked rice evenly.
Arrange meatballs over the rice.
Pour the creamy mushroom mixture over the top.
Sprinkle with mozzarella and Parmesan cheese.
Bake for 25–30 minutes, until hot, bubbly, and golden brown.
Garnish with fresh parsley before serving.
