Subway Copycat Sweet Onion Sauce
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The flavors of sweet and tangy with a hint of onion come together in this recipe for Subway Copycat sweet onion sauce. It’s the perfect condiment to add to your sandwich creation.

Ingredients to make Subway Copycat Sweet Onion Sauce
- SUGAR
- WATER
- WHITE VINEGAR
- RED WINE VINEGAR
- DIJON MUSTARD
- SESAME OIL
- CORNSTARCH
- DRIED MINCED ONION
- DRY MUSTARD POWDER
- SALT
- POPPYSEEDS
- CELERY SEED
- ONION POWDER
- PAPRIKA
- BLACK PEPPER
- GARLIC POWDER
How to Make Sweet Onion Sauce
This Subway copycat sweet onion sauce begins by adding some sugar and 2 types of vinegar to a sauce pan. You can swap out the sugar for a sugar substitute if you prefer to reduce the calories for this sauce. Now comes the flavor. You add in some Dijon mustard, sesame oil and cornstarch. That cornstarch will help thicken the sauce.
Next is all the dry ingredients. It’s even more flavor! There is a good list of them but they all help make the wonderful flavor of this sauce. There is dry mustard powder, salt, poppy seeds, celery seed, onion powder, paprika, pepper, and garlic powder. Whisk together and bring it all to a simmer. Simmer for 5 minutes while whisking.
Once you remove from the heat, allow the sauce to cool completely before adding to an air tight container. You can keep it in the refrigerator for 4 weeks. You can even freeze the sauce to keep it longer.

FOR MORE RECIPES LIKE THIS, TRY:
- Subway Copycat Bread
- Copycat of Rumbi’s House Salad
- Chicken Salad Sandwiches – Kneader’s Copycat
- Mexican Pizza (Taco Bell Copycat)

Subway Copycat Sweet Onion Sauce
Real Mom Kitchen
Ingredients
- 1 cup granulated sugar
- ½ cup water
- 6 Tbsp white vinegar
- 4 ½ tsp red wine vinegar
- 1 Tbsp dijon mustard
- ¼ tsp Sesame oil
- 1 Tbsp cornstarch
- 1 Tbsp dried minced onion
- 2 tsp dry mustard powder
- 1 tsp salt
- ¾ tsp poppy seeds
- ½ tsp celery seed
- ¼ tsp onion powder
- ¼ tsp paprika
- ¼ tsp ground black pepper
- ¼ tsp garlic powder
Instructions
- Add all of the ingredients to a medium sized sauce pan and whisk together.
- Bring to a boil over medium heat, whisking often to prevent burning. Then reduce heat to low and simmer until thickened, about 5 minutes. Whisk frequently.
- Allow to cool completely, then transfer to an airtight container. Store in the refrigerator and use within 4 weeks, or freeze for longer storage. 1 1/4 cups.
Nutrition
This recipe is adapted from Dash for Dinner.