When ready to cook, set temperature to 180℉ and preheat, lid closed for 15 minutes.
Place the butter, olive oil, and sliced onions in a cast iron pan and place directly on the grill grate with the steaks seasoned with salt and pepper.
Close the lid and smoke for 30 minutes.
Remove the smoked steaks to a separate plate and tent with foil.
Turn the temperature setting to High and add the mushrooms to the cast iron skillet. Season with the salt and black pepper. Cook the mushroom and onion mixture until soft.
Return the steaks to the hot grill to sear and cook for 3-4 minutes per side for a rare steak.
In the last minute of cooking, top the steaks with the grilled onions and mushrooms. Allow the steaks to rest for 6-8 minutes before cutting. Enjoy!
