Hi, I’m Natasha, and I’m thrilled to share my version of Subway’s sweet onion sauce recipe! This easy homemade recipe comes together in just 15 minutes, and it’s perfect for anyone who loves the sweet and tangy condiment Subway is famous for.
Subway is a favorite fast-food chain known for its sandwiches and salads, but their sweet onion sauce is a real standout. It’s a versatile, onion-flavored sauce with just the right balance of sweetness and tanginess. I’ve created a recipe that’s incredibly close to the original and perfect for elevating your sandwiches, salads, and so much more.
Whether you want to recreate a Subway-style meal at home or add a new flavor to your favorite dishes, this sauce is a game-changer.
Why I Love This Sweet Onion Sauce
This sauce has so much going for it. It’s:
- Vegan
- Gluten-free
- Preservative-free
- Oil-free
- Kid-friendly
What to Pair with Sweet Onion Sauce
This sauce isn’t just for sandwiches like tuna, chicken, or turkey subs—it’s wonderfully versatile! Here are some of my favorite ways to use it:
- Spread: Perfect on bread or sandwiches.
- Salad Dressing: Adds a tangy-sweet kick to salads.
- Dipping Sauce: Great for roasted veggies, fries, chicken, or fish.
- Marinade: Excellent for meat, chicken, or fish.
I also love pairing it with chips, baked potatoes, parathas, and pita bread. Some other recipes that pair wonderfully with it include:
- Paneer Pakora
- Aloo Bonda
- Grilled Potato Wedges
- Paneer Potato Balls
- Chicken Fry
- Gobi Pakora
- Watermelon Mango Salad
For more condiments, you might also enjoy my Mayo Ketchup Sauce!
Subway Sweet Onion Sauce Recipe
Ingredients
- 1 cup sugar
- 1/2 cup water
- 6 tablespoons white vinegar
- 1 1/2 tablespoons red wine vinegar
- 1/2 tablespoon finely minced onion
- 1 tablespoon cornstarch
- 2 teaspoons Dijon mustard
- 2 teaspoons mustard powder
- 1 teaspoon poppy seeds
- 1/2 teaspoon sesame oil
- 1/2 teaspoon onion powder
- 1/2 teaspoon salt
- 1/4 teaspoon garlic powder
- 1/4 teaspoon celery seed
- 1/4 teaspoon paprika
- 1/4 teaspoon black pepper
Instructions
- Add all the ingredients to a saucepan and whisk thoroughly to combine.
- Bring the mixture to a boil, whisking constantly to prevent clumping.
- Let it boil for 5 minutes, then reduce the heat to a simmer. Continue whisking as it simmers for an additional 5 minutes.
- Once the sauce thickens, remove it from heat and let it cool completely.
- Transfer the sauce to an airtight container and store it in the refrigerator for up to one week.
Why This Sweet Onion Sauce is Healthier
This homemade version is a better option than store-bought sauces, as it’s lower in fat and sodium. However, since it contains sugar, enjoy it in moderation.
Storage Tips
Let the sauce cool completely before storing it in an airtight container. It stays fresh in the refrigerator for up to 5–7 days. Freezing is not recommended, as it can alter the texture.
FAQs
1. Can I adjust the sweetness in this sweet onion sauce?
Absolutely! You can reduce the amount of sugar for a less sweet sauce or substitute it with honey, agave syrup, or a sugar alternative like stevia.
2. Can I make this sauce without cornstarch?
Yes, you can substitute cornstarch with other thickening agents like arrowroot powder, tapioca starch, or potato starch. Adjust the quantity as needed for the same consistency.
3. Is this recipe suitable for a low-sodium diet?
You can reduce the salt or use a low-sodium alternative to make this sauce more diet-friendly. Keep in mind that some of the other ingredients, like Dijon mustard, may already contain some sodium.
4. Can I use this sauce for grilling?
Yes! This sweet onion sauce makes an excellent marinade for grilling chicken, fish, or vegetables. Just brush it on before grilling or serve it as a dipping sauce.
5. What’s the best onion variety for this recipe?
Sweet onion varieties like Vidalia, Maui, or Walla Walla work best. However, white or yellow onions are good substitutes if sweet onions aren’t available.
6. How long does this sauce last in the fridge?
When stored in an airtight container in the refrigerator, it will stay fresh for up to 7 days.
7. Can I make a larger batch of this sauce?
Yes! You can double or triple the recipe. Just ensure you store the extra sauce properly in airtight containers.
8. Can I skip the nigella seeds or poppy seeds?
Yes, the seeds are optional but add a unique flavor and texture. If you don’t have them on hand, the sauce will still taste great without them.
9. Does this sauce work with vegan or plant-based meals?
Definitely! This sauce is already vegan and pairs well with plant-based proteins like tofu, tempeh, or seitan, as well as roasted or grilled vegetables.
10. Can I make this sauce spicier?
If you want a kick of heat, add a pinch of cayenne pepper or red chili flakes. Adjust to your taste preference.
If you try this recipe, I’d love to hear your thoughts. Feel free to leave a comment and rating. Your feedback helps me and other readers!
Subway Sweet Onion Sauce Recipe
Ingredients
- 1 cup sugar
- 1/2 cup water
- 6 tablespoons white vinegar
- 1 1/2 tablespoons red wine vinegar
- 1/2 tablespoon finely minced onion
- 1 tablespoon cornstarch
- 2 teaspoons Dijon mustard
- 2 teaspoons mustard powder
- 1 teaspoon poppy seeds
- 1/2 teaspoon sesame oil
- 1/2 teaspoon onion powder
- 1/2 teaspoon salt
- 1/4 teaspoon garlic powder
- 1/4 teaspoon celery seed
- 1/4 teaspoon paprika
- 1/4 teaspoon black pepper
Instructions
- Add all the ingredients to a saucepan and whisk thoroughly to combine.
- Bring the mixture to a boil, whisking constantly to prevent clumping.
- Let it boil for 5 minutes, then reduce the heat to a simmer. Continue whisking as it simmers for an additional 5 minutes.
- Once the sauce thickens, remove it from heat and let it cool completely.
- Transfer the sauce to an airtight container and store it in the refrigerator for up to one week.
Notes
Notes About the Recipe
- Adjusting Sweetness: If you prefer a less sweet sauce, reduce the sugar or substitute it with honey, agave syrup, or a sugar alternative.
- Thickening Options: Cornstarch works well to thicken the sauce, but you can also use arrowroot powder, tapioca starch, or potato starch for similar results.
- Ingredient Substitutions: If you don’t have nigella seeds or poppy seeds, you can skip them without significantly altering the taste. Fresh garlic can be replaced with garlic powder if needed.
- Onion Choices: Sweet onions like Vidalia or Maui are ideal, but yellow or white onions are good substitutes.
- Customizing Flavor: To add a spicy kick, include a pinch of cayenne pepper or red chili flakes. For a deeper flavor, increase the balsamic vinegar slightly.
- Storage Tips: Store the sauce in an airtight container in the refrigerator for up to 7 days. Avoid freezing, as it may affect the texture.
- Versatility: This sauce isn’t just for sandwiches—it’s excellent as a salad dressing, dipping sauce, or marinade for proteins and veggies.
- Vegan-Friendly: The recipe is completely vegan, making it a great option for plant-based meals.
