Steps

• 1

  Heat 2 adjacent zones on the flat top to medium-high heat. Heat the third zone to medium heat. Line a sheet pan with parchment paper for easier cleanup.

• 2

  Meanwhile, form the beef into 2 large patties, each about 1 ½-inches thick. Season on both sides with Traeger Burger Rub.

• 3

  Add the butter to the medium heat zone, spread it with a spatula, then place the hoagie rolls cut-side-down on the hot cooktop and toast until golden brown, about 1 minute. Transfer the toasted rolls to the parchment-lined sheet pan. (Alternatively, you can toast the rolls on the third burner while the meat cooks.)

• 4

  Place the patties on the 2 medium-high heat zones and cook undisturbed for 1 minute. Sprinkle the onion over the patties and continue to cook until the beef has started to brown on the bottom, about 1 minute. Flip the patties so that most of the onions are now hot side down. Cook for another 2 minutes, then use the spatulas to break the patties up into small pieces. Toss and cook the beef and onions until the meat is cooked through (no longer pink) and the onions have just started to brown, another 3 to 4 minutes.

• 5

  Divide the beef and onion into 4 equal rectangles, each about the size of a hoagie roll. Lay 2 slices of cheese on each pile to cover the meat. (The cheese can overlap if necessary.) Cover with a steam dome and cook until the cheese has melted, about 30 seconds.

• 6

  Spread some mayonnaise on the hoagie rolls as desired, then transfer each pile of beef and cheese to a hoagie roll. Top with iceberg lettuce and tomatoes, as desired, and bring the roll together to form the sandwich. Slice in half and serve immediately. Enjoy!