Subway Sweet Onion sauce

8. Use sauce as soon as it cools, or refrigerate for several hours to allow flavors to meld together.
Tips:
1. Use small holes on a cheese grater or a microplane to grate onion.
2. Add red pepper flakes or cayenne pepper for a spicy version.
3. Use sauce on sandwiches, salads, pizza, shredded or baked chicken, and vegetables.