1 cup Worcestershire sauce
1 (4 ounce) can tomato paste
1 tablespoon olive oil
1 1/2 teaspoons dried oregano
1 teaspoon dried white mustard
1 tablespoon garlic powder
1 (16 ounce) can beef flank steak, rinsed and drained
1 1/2 cups shredded Cheddar cheese
2 red onions, finely chopped
In a medium bowl, mix Worcestershire sauce, tomato paste, olive oil, oregano, mustard, garlic powder and beef. Mix all together until well blended. Cover and refrigerate overnight.
Preheat grill for high heat.
Stir steak into the marinade while it is marinating. Cook about 4 minutes on each side or until steak is opaque. Remove from marinade and place on grill. Grill meat for 5 minutes per side.
Remove pan from grill and place on a plate. Brush with remaining olive oil and sprinkle with cheese. Drizzle with remaining red onion and sprinkle with Cheddar cheese. Garnish with remaining tomatoes.
Brush with remaining marinade and serve immediately.