Steps

• 1

  When ready to cook, set the Traeger temperature to 375°F and preheat with the lid closed for 15 minutes.

  375 ˚F / 191 ˚C

  00:15

• 2

  Place a large cast iron pan directly on the grill grates and allow to preheat for 10-15 minutes.

  375 ˚F / 191 ˚C

  00:10

• 3

  Add 1 tablespoon of butter in the pan to coat the bottom. Add the onions, season with a pinch of salt, and pepper, and close the lid. Cook for 40 minutes stirring every 10 minutes until onions are a rich brown color.

  375 ˚F / 191 ˚C

  00:40

• 4

  Form the ground beef into four (1/4 lb) patties. Season both sides with salt and pepper to taste.

• 5

  Remove the onions from the grill. Increase the grill temperature to 500°F and preheat with the lid closed.

  500 ˚F / 260 ˚C

• 6

  Insert the probe horizontally into the center of a burger patty. Place the patties directly on the grill grates. Close the lid and cook, flipping after 5 minutes, until they reach an internal temperature of 160°F, 10 minutes.

  450 ˚F / 232 ˚C

  160 ˚F / 71 ˚C

  00:10

• 7

  Remove the burger patties from the grill. Wipe out the cast iron pan, and place it directly on the grill grates to preheat with 1 tablespoon of butter.

• 8

  Place four slices of bread into the skillet, then top with a slice of cheese, a burger patty, caramelized onions, and another slice of cheese. Spread a thin layer of mustard on the remaining 4 slices of bread and place mustard-side down over the melts. Use a spatula and press down. Close the lid and cook for 2 minutes.

  450 ˚F / 232 ˚C

  00:02

• 9

  Carefully flip the patty melts over and press down to brown the other side. Close the lid and cook until the cheese is fully melted and the bread is golden brown and crisp on both sides.

• 10

  Remove from pan and slice in half. Serve immediately with dill pickles, as desired. Enjoy!