Remove the thick center stem from each collard green leaf.
Stack several leaves on top of one another, roll them up tightly, and slice them into smaller pieces.
Rinse and wash the collard about 4 times and then soak in a large bowl of water with about ¼ cup of vinegar.
While the collard greens are soaking, dice the onion and set it aside.
Heat some bacon grease in a large Dutch oven, at least six quarts, over medium-high heat.
Once the bacon grease is hot, add the diced onion and sauté until they begin to soften and develop a little color.
Once the onions have softened, add the fresh minced garlic and continue cooking for another minute or two, just until the garlic becomes fragrant and begins to develop a little color.
Pour in the chicken stock.
Add the apple cider vinegar, Cajun seasoning, garlic powder, onion powder, crushed red pepper, and sugar.
Give everything a good stir until the seasonings are evenly distributed throughout the liquid.
Drain the collard greens and begin adding them to the Dutch oven in batches until they are cooked down a bit and are submerged in the seasoned stock.
Nestle the smoked turkey leg down into the greens.
Bring the pot to a boil the cover the Dutch oven, reduce the heat to maintain a steady simmer, and let the collard greens cook for about an hour and a half.
Carefully remove the smoked turkey leg from the pot, let it cool just enough that you can comfortably handle it, then pull all of the meat away from the bone.
Discard the bone, skin, and any tough tendons then return the meat to the Dutch oven.
Give everything a good stir so the shredded turkey is evenly distributed throughout the collard greens.
Reduce the heat to a low simmer and continue cooking for another 30 minutes.
Give the greens a taste, adjust the seasoning if needed, and serve hot with a warm slice cornbread.