Preparation:

In a sauté pan, melt the butter over medium heat. Add the ham hock and sauté until brown on both sides. Add the onion and sauté until brown. Add two  cups of water to the sauté pan , stir, scraping the bottom of the pan, until the ingredients are well combined. Remove from the stove and set aside. In a soup pot, bring the remaining cups of water and chicken stock to a boil. In a strainer, drain the soaked beans and rinse them under cold running water. Add the beans, tomatoes, and wine, and the ham hock, onion , and juice from the sauté pan  to pot. Reduce heat to medium. Cover and simmer for 2 to 3 hours. Remove ham hock from pot, allow to cool slightly, cut the meat from the bone. Add meat to soup.

Ingredients:

Chopped fresh parsley or cilantro
1/2 cup white wine
3 cups peeled and seeded tomatoes
1 cup small white beans, clean and soaked overnight
2 and 1/2 cups chicken stock
6 cups water
1 medium onion, diced
1 pork hock, with skin removed
2 tbsp butter