Prepare your toppings and condiments.
Gently shape the ground beef into 4 equal patties that are about an inch larger in circumference than your bun, ¼ lb. each. Press a divot into the center of the patties.
Heat the oil in a cast-iron skillet. Once the skillet is very hot, add the patties and season with kosher salt and fresh ground pepper, to taste. Cook for about 3 minutes per side for medium-rare (135° on a meat thermometer) or about 5 minutes per side for medium-well (150° on a meat thermometer).
Let the patties rest for 5 minutes before serving. Toast the buns with butter, if desired, and add the toppings of your choice. Be sure to read the post above for detailed instructions.