In large skillet over medium heat combine butter, mushrooms and ½ tsp. Garlic Pepper Seasoning. Saute mushrooms until tender, 3-5 minutes. Remove from skillet and cover with foil. In a large bowl combine ground beef, Ultimate Steak Seasoning, Worcestershire sauce and onions. Form into 6 burgers. Place in skillet and cook to desired doneness. Top with mushrooms and cheese. Cover skillet until cheese melts. Meanwhile, whisk together mayonnaise, Aged Balsamic Vinegar of Modena and ½ tsp. Garlic Pepper Seasoning. Place burgers on bun bottom, top with mayo and spinach. Makes 6 servings. Serve with sliced tomatoes drizzled with oil and seasoned with salt and pepper.
Make ahead & freeze
Place ground beef, Ultimate Steak Seasoning, Worcestershire sauce and onions in a gallon resealable freezer bag. Seal well, label and freeze. Thaw and prepare as directed above.