1Heat a flat griddle or large cast-iron skillet over medium-high heat for 2-3 minutes until hot. Add cooking oil and spread evenly across the surface.
2Place the beef frankfurter on the heated griddle. Cook for 4-5 minutes, rotating every minute to ensure even browning on all sides, until the hot dog develops a light char and caramelized exterior.
3Meanwhile, spread 1 tablespoon of softened butter generously on the interior of each bun half. Once the frankfurter is nearly done, place both bun halves butter-side down on the griddle beside the hot dog.
4Toast the buns for 1-2 minutes until they turn golden brown with crispy edges and the butter creates a rich, toasted aroma. Watch carefully to prevent burning.
5Remove the toasted bun halves from the griddle and place on a serving plate. Transfer the cooked hot dog into the bun immediately while both are hot.
6Season lightly with kosher salt and freshly ground black pepper if desired. Add your choice of toppings generously, Five Guys-style.