Add onions, celery, and carrots and saute until tender, about 4-5 minutes.
Add garlic and continue cooking for 1 minute.
Add ham bone and peas.
Pour in chicken broth and water.
Season with bay leaf, salt, pepper, and thyme.
Bring to a boil, then reduce the heat to low.
Cover the pot and let it simmer for 50-60 minutes, stirring occasionally until peas are tender.
Remove the ham bone and pull the ham from the bone.
Return the meat to the soup and continue cooking for 20-25 minutes or until thickened and peas have broken down.
Discard bay leaf and season with more salt if needed.
Serve immediately.
Notes
Store: Cool completely, then refrigerate in an airtight container for 5 days. The soup will thicken more as it sits—add a splash of water or broth when reheating.Freeze: Let the soup cool, then portion it into freezer-safe containers. Freeze for up to 3 months.Thaw: Thaw overnight in the refrigerator. Reheat: Reheat straight from frozen on the stovetop over low heat, stirring occasionally.Make Ahead: This soup is even better the next day! Make it ahead and let the flavors deepen overnight while it sits in the refrigerator.