Heat the EVOO in large saucepot. Add the onion, carrots, celery and bacon and sauté over medium-high heat for 5 minutes. Add the garlic and sauté for 5 minutes more. Add the lentils, bay leaf and stock and simmer for 20 minutes. Stir in the spinach and cook for another 5 minutes. Add the cooked rice or pasta and season with salt and pepper, to taste. Take bacon out at the last minute (it was there just for flavor).
Serve piping hot with grated cheese sprinkled on top and crusty bread alongside.