Mustard Herb Mix: Combine mustard, oregano, garlic and pepper. Trim fat from steak; spread mustard mix onto each side.

Place red, green and yellow peppers, onions, garlic and basil in centre of large piece of heavy-duty foil; toss together lightly. Sprinkle with oil, salt and pepper. Fold up foil to form package, sealing well.

Place steak and package on greased grill over high heat. Cook steak, turning once, for 10 minutes for medium-rare or to desired doneness; cook package until puffed. Remove steak to cutting board; tent with foil and let stand for 5 minutes.

Slice each roll in half horizontally, without cutting completely through. Slice steak and stack onto rolls; top with pepper mixture. Makes 4 servings.