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Subway Sweet Onion Sauce Recipe

Do you absolutely adore the sweet onion sauce down at Subway? Do you tend to order it with every sub you have?

Fancy making some yourself, so that you can enjoy it with sandwiches at home?

Then check out this Subway Sweet Onion Sauce recipe.

Subway Sweet Onion sauce combines the rich taste of onion with the perfect blend of tangy and sweet flavors, making it the ideal topping for roast beef and Italian subs.

Unfortunately, you can no longer get this sauce at your local Subway. They recently discontinued it in favor of their sweet onion teriyaki.

But the good news is that you can now enjoy this delicious sauce whenever you want.

Today, I’ve put together a Subway Sweet Onion Sauce recipe that has all the signature taste of the original that you can make in the comfort of your own kitchen.

Plus, it’s so easy to make that you can have it ready in less than 15 minutes.

So if you want the perfect sauce for the perfect sandwich, read on for the best Subway Sweet Onion Sauce recipe loaded with flavor.

What Do You Need To Make Subway Sweet Onion Sauce


Fresh Onion

This recipe calls for white onions for their crisp flavor, but feel free to experiment with others.

If you like a bolder taste, use red instead of white.

White Sugar

The sweetness in sweet onion sauce.

You can substitute brown sugar or add some molasses to intensify the sweetness and add a smoky flavor.

Distilled White Vinegar

The tangy vinegar balances the savory and sweet flavors.

Feel free to use apple cider instead of white.

Red Wine Vinegar

Adds another layer of tang that intensifies the flavor of your sauce.

Fresh Garlic

Garlic adds a soft, slightly bitter flavor that complements the onions perfectly.

Dijon Mustard

Adds a flavorful, spicy kick that goes beautifully with the other ingredients.


Used as a thickening agent.

Be sure to use cold water when making your slurry to avoid getting lumps in your sauce.

Dried Onion Flakes

Add more savory onion flavor and a bit of texture.

Mustard Powder

Intensifies the flavors.

Kosher Salt

I like kosher salt for its consistent flavor, but feel free to use Himalayan or coarse sea salt.

Poppy Seed

Adds a slightly nutty and fruity flavor and gives your sauce an appealing look.


Feel free to substitute smoked paprika for a more intense sweet onion sauce.

Sesame Oil

Gives the sauce an Asian flair. You can use either regular or toasted – both taste great!

Salt and Pepper

The piece de resistance, but use sparingly so you don’t overpower the other flavors.


  • Cutting board
  • Knife
  • Blender
  • Medium saucepan
  • Whisk
  • Stovetop or other heat source

How To Make Subway Subway Sweet Onion Sauce

Step One: First, peel the garlic and quarter the onion. Then, put them in a blender and puree until smooth.

Step Two: If you prefer a smoother sauce, strain the onion and garlic mixture before adding it to the saucepan.

Step Three: Now make your cornstarch slurry by adding a tablespoon of cornstarch to a couple of tablespoons of cold water. Set aside.

Step Four: Next, add all the ingredients except the cornstarch slurry to a saucepan and bring to a boil under medium heat, stirring frequently.

Step Five: Reduce the heat to low and simmer while slowly adding the cornstarch, stirring constantly.

Step Six: Allow your sauce to simmer for approximately five minutes or until it reaches your desired consistency, stirring frequently. For a thinner sauce, add a bit more water.

Step Seven: Taste your sauce, adjust any ingredients, and season with salt and pepper.

Step Eight: Let your sauce cool before serving. I like to store my sauce in a plastic squeeze bottle to make it easier to serve.


Other Things To Consider When Making Subway Sweet Onion Sauce

Pro Tips for Making the Perfect Subway Sweet Onion Sauce

  • For a smooth sauce, strain the onion-garlic mixture before adding it to the saucepan.
  • Simmering is vital to combine all the flavors and thicken your sauce, so don’t skip it.
  • Use low heat while simmering to avoid accidently burning your sauce.
  • When making your cornstarch slurry, use really cold water to prevent any lumps from forming in your sauce.

What Can I Eat with Subway Sweet Onion Sauce?

This Subway Sweet Onion Sauce recipe goes great with all your favorite homemade subs and sandwiches. In addition, this tangy sweet sauce makes the perfect salad dressing.

  • I like to mix my sweet onion sauce with teriyaki sauce for a delicious stir fry.
  • Makes a great marinade for chicken and pork.
  • Or you can blend it with mayonnaise for a tasty dip for fresh veggies.

Enjoy this delicious sauce anytime you crave that sweet onion flavor!

Make More Than You Need!

Extra sauce will stay fresh in the fridge for up to a month, though it will last much longer.

So go ahead and double the recipe.

Not only does it keep well, but your sauce will also taste better the longer it sits.

Yield: Yield: 1 ½ cups of sauce (approximately 12 servings)

Subway Sweet Onion Sauce Recipe

Subway Sweet Onion Sauce

Here is the Subway Sweet Onion Sauce Recipe that you need. Make that onion sauce you love with that perfect blend of tangy and sweet flavors, ideal for your favorite sandwiches.

Prep Time 5 minutes
Cook Time 7 minutes
Total Time 7 minutes


  • 1 medium white onion, quartered
  • 2 cloves of fresh garlic, peeled
  • 1 cup white sugar
  • ½ cup cold water
  • 5 tablespoons distilled white vinegar
  • 5 tablespoons red wine vinegar
  • 1 tablespoon Dijon mustard
  • 1 tablespoon cornstarch
  • 1 tablespoon dried onion flakes
  • 2 teaspoons mustard powder
  • 1 teaspoon kosher salt
  • 1 teaspoon poppy seeds
  • ½ teaspoon paprika
  • ½ teaspoon sesame oil
  • Salt and pepper to taste


  1. First, peel the garlic and quarter the onion.
  2. Next, add the garlic and onion to a blender with some water and puree until smooth. If you like a smoother sauce, strain the mixture before adding it to the saucepan.
  3. Make your slurry by mixing the cornstarch with two tablespoons of cold water. Set aside.
  4. In a medium saucepan, add the onion-garlic mixture, water, white sugar, white vinegar, red wine vinegar, Dijon mustard, onion flakes, mustard powder, kosher salt, poppy seeds, paprika, and sesame oil. Whisk well and bring to a boil under medium heat.
  5. Reduce the heat to low and simmer while slowly adding the cornstarch slurry, stirring frequently.
  6. Allow your sauce to simmer for approximately five minutes or until it reaches your desired consistency. For a thinner sauce, add a bit more water.
  7. Taste your sauce and adjust any of the ingredients.
  8. Season with salt and pepper.
  9. Allow your sauce to cool before serving. I recommend storing your sauce in a plastic squeeze bottle just like they do at Subway.
  10. Enjoy!


  • Use your favorite mustard instead of the Dijon to change the tang.
  • Give your sauce some kick with a pinch of ground cayenne pepper.
  • Substitute balsamic vinegar for the white and red wine for a flavorful Italian-inspired sweet onion sauce.
  • Try using different types of onions to change the flavor - red or Walla Walla sweets are excellent choices.
  • You can thin your sauce by adding more water while simmering. If it's too thin, add a bit more cornstarch.

Nutrition Information:

Amount Per Serving: Calories: 85Total Fat: 0.5gCholesterol: 0mgSodium: 190mgCarbohydrates: 20gProtein: 0g

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