1) In a large saucepan, saute the lettuce, celery, onion and carrots in butter for about 8 minutes, until the vegetables are soft.
2) Pour in the boiling water, crumbled stock cubes and chopped tomato.
3) Stir until the mixture comes to a boil, then add the rice and simmer over a low heat for about 30 minutes.
4) Season lightly with salt and paprika to taste before serving.
5) Ladle the Quick Vegetable Chowder in soup bowls and serve hot.