Wash the collard greens thoroughly to remove any dirt or grit. Remove tough stems and chop into bite-sized pieces.

In a large pot, heat olive oil over medium heat. Sauté chopped onion for about 5 minutes until translucent, then add minced garlic and cook for an additional minute.

Add the prepared collard greens to the pot and stir well. Pour in the chicken broth and add the smoked turkey leg or wing.

Bring the mixture to a boil, then reduce heat to low, cover, and let it simmer for about 45 minutes until the greens are tender.

After the greens are tender, season with red pepper flakes, salt, and pepper to taste. Stir in the apple cider vinegar.

Remove the smoked turkey, shred the meat, and return it to the collard greens. Serve hot.