Start by browning the bacon in the stock pot. Remove once it is near crisp.
Add the onions to the pot and cook until tender (about 8-10 minutes). Once they start to soften, add the garlic and about a 1/2 cup of broth. Scrape the bacon drippings off the bottom of the pan with a wooden spoon.
Add the apple cider vinegar and stir.
Add the collard greens.
Add the rest of the broth.
Bring the broth up to a simmer, adding salt and pepper. Turn to low once everything is thoroughly combined.
Cook on low for 2 hours with the lid on, coming back to check and stir, or until desired tenderness of greens is reached.