1In large soup pot on medium high, saute onion, celery, garlic, and 1 teaspoon oregano in 1 tablespoon butter/oil until soft and fragrant. Remove from pot and set aside. 2Lightly brown shrimp, scallops, and cod in remaining butter/oil (as needed) in small batches. Lightly salt each batch. Pour off and reserve liquids released from meat to add to broth later. Set aside until all are done. 3Cut potatoes into chunks and pulse in food processor until coarsely shredded. 4Put potatoes in pot with reserved vegetables, hot water, bouillon, 1/2 teaspoon oregano and Old Bay Seasoning. 5Mix well and simmer until potatoes soften. 6Combine cornstarch, half and half, and milk. 7Add milk mixture to soup pot along with reserved liquids, shrimp, scallops, and cod. 8Stir and simmer until slightly thickened.