Make a Subway Sweet Onion Sauce copycat with this delicious recipe. Perfect on sandwiches and salads!
If you loved the Sweet Onion Sauce from Subway, you’ve come to the right place. I’ve tested multiple versions of this, and created a deliciously balanced sauce with a really full flavor (without a huge ingredient list).
Read more about this sauce below or click here to head straight to the recipe.
What Is Sweet Onion Sauce?
Sweet Onion Sauce is a sauce that used to be offered by Subway for their sandwiches. The base is water, vinegar, and sweet onion with a variety of other seasonings included.
While it’s no longer offered at Subway, the demand for similar sauces definitely hasn’t gone away. I knew it was similar to Ken’s Sweet Vidalia Dressing and Veeba’s Sweet Onion Sauce. So I did a lot of experimenting based on that information and some other recipes I found to make my own copycat Sweet Onion Sauce recipe.
Testing Various Onion Sauces
I tested a few popular recipes I found as well as taste-tested the Ken’s version. The Ken’s Vidalia was balanced and had a good onion flavor. However, the homemade recipes I tried either had a raw onion taste even after simmering or simply lacked any depth to them. Some of them also had really long ingredient lists that hardly seemed worth it.
My solution? Don’t start with a raw onion, start by browning the onion in a pan and then continue to make the sweet onion sauce. This gave my sauce so much depth of flavor that I was able to create a really great balanced sauce without tons of ingredients. Plus, the color ends up more similar to that Subway sauce we’re trying to copycat.
Raw Onion Version
If you did want to try the version I created that starts with raw onion however, you can follow this recipe:
Ingredients
- 1 sweet onion, peeled, roughly chopped
- ¼ cup water
- 1 tsp. salt
- 1/2 cup sugar
- 3 Tbsp. white vinegar
- 1 and 1/2 tsp. Cornstarch
- 1 tsp. onion powder
- ½ tsp. garlic powder
Instructions:
- In a blender add onion, water and salt. Blend until smooth.
- Transfer onion mixture to a fine mesh sieve. Strain liquid from onion mixture into a small saucepan until onion mixture is nearly dry; discard onion pulp. Add sugar, vinegar, cornstarch, onion powder, and garlic powder to skillet. Wisk until no lumps remain.
- Heat skillet over medium-high heat. Bring to boiling, reduce to a simmer. Cook, whisking constantly 2 to 3 minutes.
- Remove skillet from heat, let cool at least 30 minutes. Transfer mixture to a container. Refrigerate until ready to use.
How To Make Sweet Onion Sauce
Start by slicing a Vidalia onion (or other sweet onion) into thin slices. Brown the onion in a pan with a very small amount of a neutral flavored oil such as grapeseed oil, no olive oil for this one. You want them soft and well-browned, which should take about 12 minutes.
Transfer the browned onions to a blender and add ¼ cup water and some salt. Blend until smooth and then use a fine mesh strainer to remove the onion pulp. You can save the onion pulp and add to other recipes like mashed potatoes or gravies to add flavor.
The liquid from the onion mixture goes back in your pan along with sugar, vinegar, cornstarch for thickening, and onion and garlic powder. Whisk out the lumps and then bring to a boil. Reduce the heat immediately and simmer for a few minutes, whisking constantly.
Remove from the heat and let cool. Then your homemade sweet onion sauce is ready to enjoy on a homemade submarine sandwich or on a salad. It can be stored in a container in the fridge as well.
Note: Some recipes also include black pepper, mustard, and poppy seeds which I didn’t find necessary. The poppy seeds really only add to the visual, but add them if you’d like. If you’d like a little bit of heat, you can add up to ¼ teaspoon of black pepper.
More Sauce Recipes
Want more amazing sauce recipes? Browse my full sauce recipe category or try one of these next.
Podcast Episode: Making Homemade Sweet Onion Sauce
Listen to learn how to make this recipe, along with some great tips from Christine:
Listen to more Recipe of the Day episodes here.
Print
Sweet Onion Sauce Recipe
- Prep Time: 10 minutes
- Rest Time: 30 minutes
- Cook Time: 15 minutes
- Total Time: 55 minutes
- Category: Sauce
- Method: Stovetop
- Cuisine: American
DESCRIPTION
Make a Subway Sweet Onion Sauce copycat with this delicious recipe. Perfect on sandwiches and salads!
Ingredients
- 1/2 tsp. neutral oil, like grapeseed
- 1 large sweet onion, peeled, sliced thin
- 1 tsp. salt, divided
- 1/4 cup water
- 1/2 cup granulated sugar
- 3 Tbsp. white vinegar
- 1 and 1/4 tsp. cornstarch
- 1 tsp. onion powder
- 1/2 tsp. garlic powder
Instructions
- Preheat a small nonstick skillet over medium heat. Add oil, onions, and ¼ teaspoon of the salt. Cook, stirring occasionally, until onions are soft and well browned, about 12 minutes. Adjust heat as needed to prevent burning.
- Transfer onions to a blender. Add water and remaining ¾ teaspoon of the salt. Blend until smooth.
- Transfer onion mixture to a fine mesh sieve. Strain liquid from onion mixture into same skillet until onion mixture is nearly dry.* Add sugar, vinegar, cornstarch, onion powder, and garlic powder to skillet. Whisk until no lumps remain.
- Heat skillet over medium-high heat. Bring to boiling, reduce to a simmer. Cook, whisking constantly 2 to 3 minutes.
- Remove skillet from heat, let cool at least 30 minutes. Transfer mixture to a container. Refrigerate until ready to use.
Love this recipe? I’d appreciate it if you could scroll down and add a *5 star rating* to help others know they’ll love it as well!
Notes
*Save the onion pulp for other recipes, like onion jam, soups, or mashed potatoes.
I followed the recipe directions exactly, even purchasing a blender to do so, lol. Now I fully-understand that all the so-called “copycat” recipes out there on the Net have specifcally focused on the sweet onion sauce that Subway sandwich artists squirt from a plastic bottle on sandwiches when requested BUT NOT on the delcious-tasting (in my opinion) sweet onion teriyaki sauce that the grilled strips come in when ordering that particular sandwhich. I do hope that someone can come up with a spot-on copycat recipe for that.
With that said, noteworthy, since the beginning of this year, I noticed that the online Subway menu has been changed up/revamped somewhat, moving the chicken teriyaki sandwich from Classics to Series, though not realizing that at first, I ordered the grilled chicken strips, and had a regular amount of that squirt-bottled sweet onion sauce put on it, and it made the grilled chicken strips taste somewhat better (chicken strips alone taste bland to me), however, I found it to be nothing special/nothing to write home about.
Cut-to-the-chase
The recipe I followed, I browned the onions first accordingly, and the end result, as least for me, tasted way too sugary and not really a copycat of the squirt-bottled sauce Subway uses. I am going to try it again BUT this time cutting the amount of sugar in half. :)
I’ve never had the subway sauce, so I don’t know if it tastes the same, but it is delicious!!
Glad you enjoyed, Renee!