Flank Steak Pinwheels

1. In a large resealable bag, combine the olive oil, soy sauce, red wine, Worcestershire sauce, mustard, lemon juice, 1 clove of garlic, Italian seasoning and pepper. Squeeze the bag to blend well. Pierce the flank steak with a knife, making small slits about 1 inch apart. Place the steak into the bag, and seal. Refrigerate overnight to marinate.
2. Preheat the oven to 350 degrees F (175 degrees C).
3. Crush the remaining clove of garlic on a cutting board with a large chef's knife. Sprinkle the salt over the garlic, and scrape with the blunt side of the knife to make a paste.
4. Remove the steak from the bag, and discard marinade. Spread the garlic paste over the top side of the steak. Place layers of chopped onion, bread crumbs, spinach, and cheese over the garlic. Roll the steak up lengthwise, and secure with kitchen twine or toothpicks. Place the roll in a shallow glass baking dish.
5. Bake uncovered for 1 hour in the preheated oven, or until the internal temperature of the roll is at least 145 degrees F (63 degrees F) in the center. Let stand for 5 minutes to set, then slice into 1 inch slices to serve.