Place the rice and 1 cup water in a pot; bring to the boil. Cover, reduce heat to low and simmer for 20 minutes. Place lentils in a pot with the remaining water and bring to the boil. Cook 15 minutes, or until tender.
Preheat oven to 180 degrees C.
Heat the oil in a pan over medium heat and stir in the onion and garlic. Mix in tomato, celery, carrots, courgette and 1/2 of the tomato passata. Season with 1/2 the basil, 1/2 the oregano, 1/2 the cumin, salt and pepper. Cook until vegetables are tender.
In a casserole dish, mix the rice, lentils and vegetables. Top with remaining tomato passata and sprinkle with remaining basil, oregano and cumin.
Bake 30 minutes in the preheated oven, until bubbly.