Combine oil and Signature® steak seasoning. Pour over mushrooms. Toss to coat all sides of mushrooms with marinade. Marinate at least one hour.

Drain mushrooms. Grill or broil approximately 5 minutes per side. If liquid collects under the mushroom grills, drain.

Serve mushrooms on toasted buns. Top each with 1 ounce of cheese, sliced tomatoes and lettuce.