Season Everything I'm a big fan of Gordon Ramsay and he always says you can't add a seasoned component to an unseasoned component and have the combination be magically seasoned. For example, if you are making chili, cook and season the ground beef and cook and season the vegetables, then combine.
Caramelized onions will bump your burger up a notch with the deep roasted sweetness that comes from slow cooking. Add bacon and now you have sweet and salty harmoniously working together to heighten your burger to insane levels never achieved previously in your culinary career. Must be hard, right? Caramelized onions might take an hour or so to complete but patience is a better work describing the process.
Slicing your onions evenly ensures they are all equally caramelized. The best way to accomplish this is to cut the onion in half and then slice in wedges. Instead of slicing vertically, slice at an angle towards the center. While the onions are not exactly the same size, they are much closer than any other method. What is gone are the wide edge pieces that always look peculiar and don't cook at the same speed.
While you are perfecting your onion skills, dice the bacon and cook on medium till it is crispy. Use the same thick pan you will be using to caramelizes the onions as the oil from the bacon will be kept for flavor and prevent the onions from sticking to the pan.
Once the bacon is crispy, add the onion slices and cook. Store frequently at this temperature. After 10 minutes, turn the temperature to low and add salt, pepper, and brown sugar. Cook for approximately an hour until the onions are a deep golden to dark brown, depending on the level caramelization you desire. I have chosen a nice golden brown for this recipe.
Make the onions ahead of time to create a more relaxed atmosphere in your kitchen. They will keep fine for hours unheated under a cover. You can even store them in the fridge if you want to make them the night before but I'm all about freshness so I prefer cooking them at the time they will be eaten.