6ouncesbella mushrooms, wiped clean with a damp paper towel and sliced
1tablespoonfinely minced shallots
½teaspoonfresh thyme, finely minced
Salt and pepper to taste
For the smash burgers:
Wipe mushrooms clean with a damp paper towel. Place in a food processor and pulse in 2 second increments 8-10 times until finely chopped, scraping down the sides of the bowl as needed. The mushrooms should look like minced garlic.
Transfer the mushrooms to a large bowl. Add the steak seasoning, worcestershire sauce, and black pepper. Stir to combine. Add the ground beef and gently fold the ingredients together with a rubber spatula. Carefully divide the mixture into four loose mounds - each should be about the size of a baseball. Try to handle the meat as little as possible - the shaggier/looser the mixture, the better! Set aside.
Heat a cast iron skillet over medium-low heat. Add a drizzle of oil and a dab of butter. Toast the burger buns face side down in this mixture for about 2 minutes until golden brown. Transfer to a plate.
Return the skillet to medium heat. Add the sliced mushrooms and shallots, along with a drizzle of olive oil and a dab of butter. Saute until the mixture is golden brown. Add the fresh thyme, worcestershire, hot sauce, and salt and pepper to taste. Stir to heat through, about 2 minutes. Transfer to a bowl and cover with foil to keep warm.
Wipe the skillet dry with a paper towel (as needea)nd return to medium heat. Add a drizzle of oil. Carefully transfer two mound of the beef mixture to the sillet. Smash each mound firmly with a metal spatula to a thickness of about ½ inch. Cook for 3 minutes on each side until golden brown and crisp around the edges (internal temperature should reach 155 °F for medium-well). Once you flip the patty to the second side, add a slice of Swiss cheese to melt and cook an additional 3 minutes. Transfer to a plate and tent with foil. Repeat this process with the other two mounds of beef.
To assemble the burgers, place a smashburger patty on a toasted bun. Top with some of the mushroom mixture and fresh arugula. Enjoy hot!