Add a drizzle of olive oil to a large pot and saute diced onion until caramelized.

Add ham to pot and brown slightly.

Deglaze pot with chicken broth, scraping the bits stuck to the bottom for added flavor.

Add vinegar and greens. Cover with lid and reduce heat, boiling on medium heat with lid in place for 45 minutes to 1 hour. Check occasionally to make sure liquid remains in the pot.

Add salt and pepper and test for tenderness. Greens are done once they’ve softened considerably. Serve warm.