Subway Sweet Onion Sauce1/2 cup light corn syrup1 tablespoon minced white onion1 tablespoon red wine vinegar2 teaspoons white distilled vinegar1 teaspoon balsamic vinegar1 teaspoon brown sugar1 teaspoon buttermilk baking mix1/4 teaspoon lemon juice1/8 teaspoon poppy seed1/8 teaspoon salt1 pinch cracked black pepper1 pinch garlic powder1. Combine all ingredients in a small microwave-safe bowl.2. Heat mixture uncovered in the microwave for 1 to 1 1/2 minutes on high until mixture boils rapidly.3. Whisk well, cover and cool.4. Alternatively, bring to a boil on top of stove.