4 cups cooked navy beans or small white beans** or 2 (15-ounce) cans navy beans, rinsed and drained
1 Tablespoon olive oil
1 onion, chopped small
2 leeks, white and light green parts, cut into thin half slices
2 teaspoons minced garlic
1 teaspoon dried thyme
1/2 teaspoon dried Greek oregano
1 (14.5-ounce) can petite diced tomatoes
2 cups diced ham
4 cups ham stock (or use chicken stock with a little Ham Flavored Concentrate added)
1 (16-ounce) can refried pinto beans
generous amount fresh ground black pepper (do not add salt, the ham stock and ham will make it salty enough)
2 Tablespoons Spanish sherry vinegar or other flavorful vinegar of your choice
Dice the onion into pieces smaller than 1/2 inch.
Cut off dark green ends of the leeks, cut in half lengthwise, then slice the leeks into thin half slices.
Put leeks in salad spinner or small colander and rinse well with cold water and spin dry or let drain.
Heat olive oil in a heavy soup pot, add onions and leeks and sauté until they start to soften, about 3-4 minutes.
Add minced garlic, dried thyme, and dried Greek oregano and sauté about 2 minutes more.
Add diced tomatoes and juice, cooked beans, diced ham, and 3 1/2 cups of the ham stock and let mixture come to a simmer.
Mix the remaining 1/2 cup ham stock with the can of refried beans, then stir into the stew.
Season generously with fresh ground black pepper and let the mixture simmer on low for 1-2 hours, or until the stew has thickened and flavors have blended to your liking.
Stir in 2 Tablespoons Spanish sherry vinegar (or any vinegar you like the flavor of) and serve hot.