Preheat the oven to 190C/375F.
In a large pan, placed over medium-high heat, heat up olive oil and saute onions and peppers for 10 minutes. Add ground chicken and break it up with a wooden spoon. Cook for 5 minutes. Add in spinach and garlic, cook for 1 minute.
3 tablespoon olive oil, 500 g 1 pound ground chicken, 1 medium white onion, 150 g 5 oz frozen spinach, thawed and dried, 1 medium red bell pepper, 1 medium yellow pepper, 3 garlic cloves
Season with salt, pepper, garlic, herbs and worcestershire sauce, add tomato paste and cook for 1 minute.
1 tablespoon dry italian herbs, salt and pepper to taste, 2 tablespoon tomato paste, 2 tablespoon worcestershire sauce, 2 thyme sprigs
Pour in tomato sauce and chicken stock. Mix well and bring to a boil. Combine rice with the sauce and cook on a low heat, covered with a lid, for 15 minutes.
2 cups chicken stock, 400 ml 14 oz tomato sauce, 1 cup uncooked long-grain rice
Transfer rice mixture into a baking pan (it might still have some liquid left that will absorb after baking). Top the casserole with cheese and bake for 10 minutes.
1 cup cheese