evenly divide the ground beef into 4 equal portions. Without overworking the meat, form into patties (no you do not add anything to the meat yet!!!!) Your patties should be approximately 5 inches long and only 1/4 inch thick. Set aside.
Heat a large cast iron skillet over medium to medium-high heat (somewhere in between the two) for 5-8 minutes so that the skillet is very hot. Add the avocado oil to the hot skillet.
Immediately before cooking your burgers in the skillet, generously season both sides of the patties with plenty of kosher salt and coarse black pepper. Gently place the patties into the hot skillet and cook until the burgers have a nice, browned crust on both sides and are cooked to your liking. They cook quickly, about 2-3 minutes per side.
Transfer cooked patties to a plate and let rest while you toast your buns (if you are using cheese, place the slice of cheese on top of the burgers while they rest to allow it to melt a bit). Heat a skillet over medium heat. Smear about 1/2 tbsp of butter on each side of the buns and toast until golden brown on each side, about 2-3 minutes a side.
To serve, smear burger sauce on each side of the buns. Add the burger patty and load the burger up with the toppings you desire-- I added lettuce, tomato and onion on top of mine for a classic, but by all means get as fancy as you want!! ;)
Serve and enjoy!!