Vegetable Oil Soy Sauce Lemon Juice Mustard Worcestershire Sauce Minced Garlic Pepper Salt Beef Sirloin Mushrooms Green Bell Pepper Red Bell Pepper Red Onion Cherry or Grape Tomatoes
Place vegetable oil, soy sauce, lemon juice, mustard, Worcestershire sauce, garlic, pepper and salt together in a large zippered plastic bag. Close and shake to mix. Add the beef and mushrooms and seal the bag.
Cut Green peppers, red peppers and onions. Put pieces of green bell pepper, beef, red bell pepper, mushroom, tomato and onion onto skewers.
Transfer the marinade into a pan and bring to a boil. Remove from heat and use for basting. Cook skewers on the grill.