- Heat the oil in a heavy soup pot. Add the chorizo, onion, and pumpkin; cook over high heat, stirring, for a few minutes. Add the leeks, garlic, and tomato, and cook for 3 minutes more.
- Tie the celery, parsley & bay leaves together w/kitchen string and add along with the lentils to the soup pot. Add enough water to cover the lentils by 2 inches, and bring to a boil. Reduce the heat, and simmer covered for about 20 minutes.
- Season with salt and black pepper, add the potato cubes, and simmer until the vegetables are soft, 15 minutes. If necessary, add more water.
- Before serving, discard the herb bundle, and taste for seasoning. Serve the soup piping hot, garnished with the parsley.