To make a Bacon Onion Marmalade, fry the bacon from both sides in oil until it is crisp and nicely cooked. Drain the bacon on a paper towel, so that the towel soaks up the excess oil. Chop the bacon into very small pieces and keep it aside. Heat butter and oil in a pan. Add onions, garlic, and chopped bacon. Next, add salt, black pepper, chili flakes, brown sugar, and cook it for about 40 to 50 minutes. Add apple juice, red wine vinegar, cook for another 10 to 15 minutes and your Bacon Onion Marmalade is ready. Adding a splash of bourbon once the marmalade is done is a great variation of this recipe.