Copycat Sweet Onion Sauce Recipe

This easy copycat recipe recreates a popular sub shop’s crave-worthy Sweet Onion sauce at home with ingredients you likely have on hand! Simmer onions, sugar, and spices into the perfect tangy and sweet dipping sauce for sandwiches, chicken tenders, or veggies in just 10 minutes.

Homemade Sweet Onion Sauce

I’ll admit that it’s been a LONG time since I’ve been out to eat at a sandwich shop. (Thank you celiacs!) But those cravings for my favorites always come back once in a while.

My favorite sub at Subway used to be the Sweet Onion Teriyaki Chicken. That sauce was so good! There’s nothing like a yummy chicken sandwich that tastes both tangy and sweet!

But hey…as it turns out, we can make it at home too! This recipe is naturally gluten-free and dairy-free.

Let’s get cooking!

Ingredients in Sweet Onion Sauce

• Sugar. Yes, this recipe uses sugar; it’s a SWEET onion sauce! You might be able to replace some or all of this with honey for a sweetener.
• Water. You may need more or less depending on if you need to thin down your sauce.
• White Vinegar and Balsamic Vinegar. Both kinds of vinegar are needed to give this sauce its tangy kick.
• Onion. This is fresh onion that should be grated to be used in this recipe. I used white onion for this recipe. Vidalia and yellow onions would work as well. If you don’t feel like the fresh onion gives enough flavor, add in a little dried onion flakes, minced onion, or onion powder as well. NOTE: If you do not like pieces of onion in your sauce, run the onion through a garlic press to get the juice out and use the liquid instead.
• Garlic. This is fresh garlic that should be chopped finely to use in this recipe.
• Cornstarch. If you don’t want to use cornstarch, you can use another starch like arrowroot, potato starch, or tapioca starch instead.
• Mustard. Only a little bit is needed. I use regular yellow mustard for this recipe. I’ve not tried Dijon mustard, but that might be a good substitute as well.
• Sesame oil. Sesame oil will have the best flavor, but you can use olive oil in a pinch.
• Salt, Poppyseeds, Garlic granules, Celery seed, Black pepper. These are the additional spices needed to flavor the sauce. Replace the celery seed and salt with celery salt if you have it. You can also replace the poppy seeds with black sesame seeds as well like I did in the pics!

Step-by-Step Instructions for Making Onion Sauce

Add all the ingredients into a pot and bring to a boil, whisking constantly.

Let it simmer for 7-10 minutes – until the sauce looks glossier.

After the sauce thickens, remove from heat and allow to cool.

Store this yummy Subway copycat sauce in an airtight container or a jar in the fridge for up to 1 week.

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Sweet Onion Sauce Recipe

This easy copycat recipe recreates Subway's craveworthy Sweet Onion sauce at home with ingredients you likely have on hand! Simmer onions, sugar and spices into the perfect tangy and sweet dipping sauce for sandwiches, chicken tenders or veggie dipping in just 10 minutes.

Course Side Dish

Cuisine American

Keyword Sweet Onion Sauce

Prep Time 5 minutes

Cook Time 5 minutes

Total Time 10 minutes

Servings 4 servings

Calories 222 kcal

Creator Merissa

Ingredients

• 1 cup sugar
• 1/2 cup water
• 6 tablespoons white vinegar
• 1 tablespoon balsamic vinegar
• 1 1/2 tablespoon onion freshly grated
• 2 cloves garlic grated
• 1 tablespoon cornstarch
• 1 teaspoon mustard
• 1 teaspoon poppy seeds
• 1/2 teaspoon sesame oil
• 1.2 teaspoon salt
• 1/4 teaspoon garlic granules
• 1/4 teaspoon celery seed
• 1/4 teaspoon black pepper

Instructions

1. Add all the ingredients into a pot and bring to a boil, whisking constantly.
2. Let it simmer for 7-10 minutes – until the sauce looks glossier. After the sauce thickens, remove from heat and allow to cool.

3. Store in an airtight glass jar in the refrigerator for up to 1 week.

Nutrition Facts

Sweet Onion Sauce Recipe

Amount Per Serving

Calories 222 Calories from Fat 9

% Daily Value*

Fat 1g2%

Saturated Fat 0.1g1%

Polyunsaturated Fat 0.4g

Monounsaturated Fat 0.3g

Sodium 716mg31%

Potassium 31mg1%

Carbohydrates 54g18%

Fiber 0.4g2%

Sugar 51g57%

Protein 0.4g1%

Vitamin A 2IU0%

Vitamin C 1mg1%

Calcium 22mg2%

Iron 0.3mg2%

* Percent Daily Values are based on a 2000 calorie diet.

Ways to Use Sweet Onion Dressing

This tangy sauce can be used in multiple ways. Here are some ideas!

• As a salad dressing for salads.
• Use as a dipping sauce for chicken, especially chicken nuggets.
• Drizzle over the tuna on a tuna sandwich for more flavor.

More Sauce Recipes

• Sweet and Sour Sauce
• Easy Orange Sauce Recipe
• Stir Fry Sauce
• Homemade Soy Sauce Recipe
• Alfredo Sauce Recipe

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Merissa Alink

Merissa has been blogging about and living the simple and frugal life on Little House Living since 2009 and has internationally published 2 books on the topic. You can read about Merissa’s journey from penniless to freedom on the About Page. You can send her a message any time from the Contact Page.

This recipe for Sweet Onion Sauce was originally posted on Little House Living in December 2023.