Place the mushrooms and oats in the bowl of a food processor fitted with a metal blade. Pulse until finely chopped. Add the beef, seasoning blend and salt. Pulse until well combined. Form the mixture into six 4-inch patties.
Set a greased grill pan over medium-high heat. Place the burgers on the pan, and cook, without turning, for 5 to 7 minutes. Flip burgers and cook for an additional 5 minutes. Add cheese and cook for 1 minute more. Serve on hamburger buns with traditional toppings.