Grilled flat iron steak with brown sugar chive marinade recipe

Ingredients

• 1/2 cup soy sauce
• 1/3 cup vegetable oil
• 1/4 cup Worcestershire sauce
• 2 tablespoons brown sugar (light or dark, but dark is best)
• 2 cloves garlic, minced
• 2 tablespoons minced chives
• 1 1/2 teaspoons freshly ground black pepper
• 2 teaspoons balsamic vinegar
• 1 flat iron steak (or more)