Thank you to Greensbury Market for the ground beef that inspired this recipe.
Set the EGG for direct cooking without a convEGGtor at 400°F/204°C; add the Cast Iron Plancha Griddle to the EGG to preheat.
Form the ground beef into 4 – ½ lb. patties and set aside.
Add the olive oil to the plancha griddle and sauté the onions and mushrooms for 2 minutes. Place the beef patties on the cooking grid. Season the burger patties with the Big Green Egg Classic Steakhouse Seasoning. Cook for about 2 minutes and flip. Cook for another 2 to 3 minutes and then place some of the mushrooms and onions on top of the patties; add a piece of cheese on top. Cook for 1 minute longer and remove the patties from the EGG.
Once the burger patties are cooked, toast the hamburger buns on the seasoned plancha. Place one burger patty on each of the toasted buns and top with your favorite condiments. Enjoy!