Cook the bacon on a raised grid on a sheet pan at 400° in the oven for 20 minutes.
Press out the hamburger patties round. Add a thumbprint to the center, as it does help keep the cooked patty flat. Make sure the patty is larger than the bun, as it will shrink as it cooks.
Preheat the grill to about 400° and add the cast iron skillet with a little bit of oil. Let the skillet come up to temperature.
Add the patty to the skillet and let it cook for about two to three minutes. Turn it over and let that cook for the same amount of time. They are done when fully cooked at 160°F.
Layer the ingredients in the following order: Bun, cheese, patty, cheese (again!), ketchup and mustard, bacon, pickles, onion, tomato, lettuce and then the burger top. It is ready to serve!
Notes
Preheat the Cast Iron or Griddle: Let the cast iron skillet come up to temperature. It usually only takes a few minutes for it to come to temp on a hot grill, but it is best to add a drop or two of water to the pan. If it immediately sizzles, it is ready. It is usually best to wait another two or three minutes after you think it is ready - just to be safe.Don't Press the Patty: Don't press down on the patty. While this is tempting, it squeezes out some of the juices and really impacts the end result.Burger Sizing: Form the burger patty about ½" larger than the bun. It will shrink as it cooks.Storage: Keep unused burgers in a refrigerator safe container for up to two or three days. These reheat wonderfully and serve as great leftovers as a stand alone burger or mixed in with veggies.Assembled burgers do not save well. The buns quickly become soggy. It's best to keep the ingredients separated until it is time for assembly and serving.Meal Prep: To save time, slice the onions and tomatoes ahead of time. It is also easy to form the patties early and have them ready for grill day.