Combine potatoes and water in a medium bowl.
Melt 3 tablespoons butter in a large soup pot over medium heat. Add leeks and celery; sauté 5 minutes or until tender. Add potatoes and water; bring to a boil. Cover, reduce heat, and simmer 12 minutes or just until tender.
Stir in half-and-half and corn. Cover, and cook over medium heat 5 minutes or until thoroughly heated. Add scallops, salt, black pepper, and red pepper, if desired; cook 3 minutes.
Stir a pat of butter into each serving, if desired. Serve immediately.
Wine note: "Try Puerto Fino sherry by Lustau ($15) from Spain. Soup can be tricky. It is often not paired well with any wine because of incompatible flavors. This is a risk I will take here because at one time I wasn't accustomed to sherry and its admirable traits until I had some that really floored me. Sherry alone can be austere to those who do not know what to expect, but open-minded diners anticipate dazzling flavors from honey and peaches to tar and roses."--Franklin Ferguson, wine director and bar manager, Citrine restaurant, Los Angeles, CA.