Preparation Steps
Take the thyme sprigs and bay leaf, and wrap the reserved green leek top around.
Tie with butchers twine to secure.
Place the coriander seeds, peppercorns, and cumin seeds in the middle of a coffee filter or small piece of cheesecloth, and tie into a bundle using butchers twine.
Set aside.
Heat the olive oil in a large stockpot over medium heat.
Add leeks, carrots, and celery.
Saute for 5 minutes or until softened.
Add garlic and saute for another minute.
Add tomato paste and saute for another minute.
Add the beans, ham bone, the herb bundle and the spice bundle, and enough water to cover.
Bring to a boil and reduce to a simmer, partially covering.
Allow to simmer for 1 hour.
Add the diced ham and chipotle chile powder and stir in.
Allow to simmer until beans are soft and are just beginning to break open, another 1 1/2 to 2 hours.
Adjust seasoning to taste.
Remove ham bone and pull any remaining ham from the bone and return to pot.
Remove herb bundle and spice bundle, and serve.