Put the beans in a large saucepan and cover with cold water by 2-inches. Bring to a boil and lower the heat to a simmer. Cook for 5 minutes; remove from the heat, cover and set aside for one hour. Drain and reserve.

In a large soup pot heat the butter or oil over medium heat. Add the onions, celery and carrots, and saute until wilted and golden, about 10 minutes. Add the garlic and thyme and saute for 3 minutes more. Add the beans, hocks, water or stock, and bring to a simmer. Cover, adjust the heat to maintain a gentle simmer, cook until beans and meat are tender, about 1 1/2 hours.

Turn the soup off. Remove the hocks from the soup, set aside to cool. Remove the meat from the hocks, discarding the bones, fat and skin. Cut the meat into small cubes. Puree the soup, with an immersion blender or in batches in a blender. Heat the soup to a simmer with the meat. Season with salt and pepper. Add the sherry. To serve, divide the soup among warmed bowls, and top with one or more of the garnishes, if desired.