In a large pot, combine 9 cups of chicken stock and 3 cups of water. Add the chopped onions, minced garlic, and ham hocks to the pot.

Bring the mixture to a boil over medium-high heat. Once boiling, cover the pot and let it cook for 15 minutes. After 15 minutes, remove the lid and add half of the collard greens to the pot.

Cover the pot again and continue cooking for 10 minutes. This will allow the first batch of greens to begin to wilt and cook down.

After 10 minutes, add the remaining collard greens to the pot. Cover and cook for another 10 minutes.

Once the greens have cooked down, season with 2 teaspoons of salt, 1 teaspoon of black pepper, and 1 teaspoon of red pepper flakes. Pour in the 4 tablespoons of white vinegar. Stir everything well to ensure the greens are evenly coated with the seasonings.

Cover the pot and reduce the heat to low. Allow the collard greens to simmer for 1 hour. This slow cooking process will ensure the greens are tender and infused with flavor.

Once cooked, serve the collard greens hot, preferably alongside your favorite soul food dishes.