- 16 cups water
- 1 1-pound piece smoked pork shoulder or ham shanks, cut into 1/2-inch cubes
- 3 pounds coarsely chopped turnip greens, kale, or mustard greens, thick stems discarded
- Thinly sliced sweet onion (such as Vidalia or Maui; optional)
- Combine 16 cups water and pork in very large deep pot; bring to boil. Reduce heat to medium-low, cover, and simmer 1 1/2 hours. Using sieve or slotted spoon, remove pork pieces from broth and discard. DO AHEAD: Broth can be made 2 days ahead. Cool slightly. Chill uncovered until cold, then cover and keep chilled.
- Return broth to boil. Season lightly with salt and pepper. Add greens to broth by large handfuls, allowing greens to wilt slightly before adding more. Cover and boil gently over medium heat just until greens are tender, about 10 minutes for mustard greens and 20 minutes for turnip greens or kale.
- Drain, reserving cooking liquid. Transfer greens to serving bowl. Moisten generously with cooking liquid (reserve remaining cooking liquid for another use). Season to taste with salt and generous amount of pepper. Scatter onion over, if desired, and serve.