3/4 cup sunflower oil
1/4 cup maple syrup
1/4 cup low sodium soy sauce
1 small onion, chopped
3 cloves garlic
2 tablespoons balsamic vinegar

Combine all the ingredients in a blender/food processor.. Take your flank steak and sprinkle with fresh ground black pepper on bother sides. Place in a glass dish and pour over the marinade. Flip over and ensure both sides are covered. Seal with plastic wrap and place in the frig overnight (or at least 8 hours).

Bring to room temperature before you place it on the BBQ.