Are you looking for a recipe for sweet onion sauce that is made with real onions? Well then you are in the right place! This recipe for sweet onion sauce is made with perfectly caramelized onions rather than dehydrated onion or onion powder. That means that it is so much more flavorful than the alternatives.
This is the perfect option if you are looking for a sweet onion sauce recipe that gives Subway’s sweet onion sauce a run for its money.
What is in sweet onion sauce?
What is in sweet onion sauce? Here are all the ingredients you need to make sweet onion sauce.
- Sweet onion. The first ingredient you will need to make sweet onion sauce is an onion. For best results, you should use a sweet onion such as a vidalia onion. The onion is cooked before it is added to the sauce to ensure that the sugars in the onion caramelize.
- Red wine vinegar. The next ingredient you need to make sweet onion sauce is red wine vinegar. The red wine vinegar provides some acidity that enhances the sweetness of the caramelized onions. If you do not have red wine vinegar, white wine vinegar would also be an appropriate substitute.
- Vegetable oil. Vegetable oil is used in two places in this recipe for sweet onion sauce. First, the vegetable oil is used to caramelize the onions for the sauce. After the onions are done cooking, some additional vegetable oil is added to balance out the acidity of the red wine vinegar.
- Water. Some water is added to thin out the sweet onion sauce.
- White sugar. A little bit of white sugar is used in this recipe for sweet onion sauce. The sugar adds a little extra sweetness that compliments the natural sweetness of the caramelized onions.
- Cornstarch. Some cornstarch is added to thicken the sweet onion sauce. The cornstarch should be mixed with equal parts cold water before it is added to the sauce to ensure that it does not clump up.
- Mustard. Mustard is added to give the sauce additional flavor. We recommend using a high quality brown mustard such as this Inglehoffer Stone Ground Mustard.
- Salt. Finally, some salt is added to enhance the other flavors in the sauce. The salt also helps to draw the water out of the onions so that they cook faster.
How do you make sweet onion sauce?
How do you make sweet onion sauce? Here are all the steps you need to take in order to make sweet onion sauce.
- Dice the onions. The first step in making this sweet onion sauce is to dice the onions. The onions should be chopped into relatively small pieces as they will be added to the sauce whole.
- Cook the onions. After you dice the onions, it is time to cook the onions. The onions should be sprinkled with salt and cooked in vegetable oil until they begin to caramelize. When they are done, the onions should have a nice medium brown color.
- Make the cornstarch slurry. When the onions are almost done cooking, you can combine the cornstarch with equal parts water to to make the cornstarch slurry.
- Combine the ingredients. When the onions are done cooking, it is time to combine all of the ingredients for the sweet onion sauce. You can simply add the other ingredients to the pot you cooked the onions in. You should wait to add the cornstarch slurry to the sauce until the water and red wine vinegar have already been added.
- Thicken the sauce. After you combine all the ingredients for the sweet onion sauce, continue to cook the sauce for a few minutes until the sauce thickens.
How do you store sweet onion sauce?
How do you store sweet onion sauce? Sweet onion sauce should be stored in the refrigerator in an airtight jar or food storage container. If stored in an airtight container, this sweet onion sauce will keep for up to three days.
How do you reheat sweet onion sauce?
How do you store leftover sweet onion sauce? This sweet onion sauce is easy to reheat. All you need to do to reheat this sweet onion sauce is microwave it on full power for 30 – 60 seconds or until it is heated throughout. We recommend putting a paper towel over the top of the sweet onion sauce so that the sauce does not splatter on the side of the microwave.
Sweet onion sauce
- 1/2 sweet onion (about 1 cup chopped)
- 1/4 cup red wine vinegar
- 1/4 cup water
- 1/4 cup vegetable oil
- 1 tbsp white sugar
- 1 tsp cornstarch (plus 1 tsp cold water)
- 1/2 tsp mustard
- 1/4 tsp salt
- Chop the onions into small pieces.
- Add 2 tbsp of the vegetable oil to a medium sized pot then heat the pot over medium heat. Add the onions and sprinkle the salt over the top of the onions. Cook the onions for 25 – 30 minutes or until the onions reach a medium brown color. Stir the onions occasionally. Add small amounts of water as necessary to deglaze the pan.
- Mix the cornstarch with equal parts cold water.
- Add all of the remaining ingredients to the pot with the onions. Wait to add the cornstarch until the water and vinegar have already been added to the pot.
- Cook the sweet onion sauce over medium low to medium heat until the sauce starts to thicken.
Substitutions for sweet onion sauce
- Sweet onion. If you do not have a sweet onion, you can also use another type of onion. If you use another type of onion, you may need to cook the onion a little longer to ensure that the sugars in the onion caramelize properly.
- White sugar. If you do not have white sugar, brown sugar will also work in this recipe. A 1:1 substitution will work just fine. Brown sugar is more acidic than white sugar, so the sauce might have a slightly more acidic flavor if brown sugar is used.
- Red wine vinegar. If you do not have red wine vinegar, you can also use white wine vinegar. A 1:1 substitution will work just fine.