Heat oil and sherry or water in a large heavy saucepan until bubbling. Add onion and sauté 5 minutes, stirring frequently to prevent browning. If mixture appears dry, add a Tablespoon or two of water. Add carrot, celery, bay leaf, potatoes, and stock. Cover pan and bring to a boil. Reduce to medium heat and cook 10-15 minutes or until potatoes are tender.

Add milk or soymilk and corn and simmer 3 minutes, or until corn is tender (if using soymilk, be careful not to let the mixture come to a boil.) Remove bay leaf. Purée one cup of the soup and return it to the pot. Season with cayenne and black pepper to taste.