Don't be overwhelmed by the large ingredient list, this sweet onion sauce takes less than 15 minutes of work for a condiment that lasts almost forever. It's a great addition to anyone's sandwiches and it couldn't be easier to make. It's just a bonus that it doesn't have any funny preservatives. This recipe was created by trialing and taking bits from both this and this recipe. The recipe from The Spice Guru made an incredible base recipe, though it was too sweet and too salty - the changes have improved on their already very strong recipe.
This recipe is part of a series recreating all the best recipes from Subway. You can find this mega-post here.
Usually I have some recommendations on how to you can make recipes easier with my favourite kitchen tools, but for this, all you really need is a pot (small in size is fine) and a whisk. For a bit of an easier time, a garlic press is recommended, but you can use a cheese grater for grated onion if you don't have a garlic press or juicer to extract onion juice.
The only hard part about this recipe is being able to wait for it to reach optimal flavour during the 6 hour rest time. It smells amazing when you're making it but trust me, you want to let it rest for the best taste.
Sweet Onion Sauce Ingredients
With a whopping 17 ingredients, this recipe may seem overwhelming, but there's only one ingredient found outside a spice cabinet or pantry. The less common ingredients like sesame oil and poppyseeds may not be in every household, but they last forever.
The only non-shelf stable ingredient is onion juice, which comes from taking an onion through a juicer (or preferably a garlic press) to get the flavour but not the texture. As mentioned above, you can grate the onion instead if you don't mind a slightly stronger and milled onion taste/texture.
Other Sauce Recipes
- Donair Sauce
- Taco Bell Quesadilla Sauce
- Subway Mayonnaise
- Subway Chipotle Southwest Sauce
- Zero Waste Pesto
Subway's Sweet Onion Sauce
- ⅔ cup sugar granulated
- ½ cup cold water
- 6 tablespoon vinegar white or distilled
- 1 ½ tablespoon red wine vinegar
- 1 tablespoon cornstarch or arrowroot powder
- 1 tablespoon minced onion flakes
- 2 ½ teaspoon dijon mustard
- 2 ½ tsp mustard powder
- ¾ teaspoon celery salt
- ¾ teaspoon fresh onion juice use a garlic press to juice
- 1 teaspoon poppyseeds
- ½ teaspoon onion powder
- ¼ teaspoon garlic powder
- ½ teaspoon salt
- ⅓ teaspoon paprika
- ¼ teaspoon black pepper
- 1 - 2 drops sesame oil
- In a small pot, whisk together all ingredients over medium high heat - allow to bring to a boil while whisking constantly.
- Reduce heat to low and simmer, stirring until thickened - around 5 minutes.
- Allow to cool in the refrigerator overnight.
- This sauce keeps indefinitely if stored in a sealed jar in the fridge.