Here's a copy cat recipe for Subways Sweet Onion sauce:

[cheri]

This is the sauce they use on their new chicken teriyaki sandwich. I haven't tried this recipe yet, but it looks good!

The Sweet Onion Chicken Teriyaki Sandwich is one of Subway's biggest new product rollouts in chain history. The sandwich is made with common ingredients: Teriyaki glazed chicken breast strips, onions, lettuce, tomatoes, green peppers, and olives. But what sets it apart from all other teriyaki chicken sandwiches is Subway's delicious Sweet Onion Sauce. You can ask for as much of the scrumptious sauce as you want on your custom made sub at the huge sandwich chain, but you won't get any extra to take home, even if you offer to pay. Now you can add a clone version of the sauce to your home-built sandwich masterpieces whenever you want.

1/2 cup light corn syrup
1 tablespoon minced white onion
1 tablespoon red wine vinegar
2 teaspoons white distilled vinegar
1 teaspoon balsamic vinegar
1 teaspoon brown sugar
1 teaspoon buttermilk powder
1/4 teaspoon lemon juice
1/8 teaspoon poppy seeds
1/8 teaspoon salt
pinch cracked black pepper
pinch garlic powder

1. 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. (http://www.topsecretrecipes.com)

Makes about 2/3 cup.