Balsamic Marinated Flank Steak

Bahan-bahan (4 porsi)

• 2 pounds flank steak
• 3 tablespoons olive oil
• 3 tablespoons balsamic vinegar
• 3 tablespoons soy sauce
• 2 tablespoons Dijon mustard
• 1 tablespoon Worcestershire sauce
• 3 cloves garlic (minced)
• 1 tablespoon fresh rosemary (chopped)
• 1 teaspoon black pepper
• ½ teaspoon red pepper flakes (optional)