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A bottle of sweet onion sauce, being added to a homemade sub.

Sweet Onion Sauce {Subway Copycat Recipe}

Make this favorite Subway-inspired sauce in the comfort of your own home! Sweet onion sauce has a strong onion flavor, balanced with sweetness, and just a touch of sour.
4.62 from 95 votes
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Course: Sauces
Cuisine: American
Prep Time: 10 minutes
Cook Time: 5 minutes
Total Time: 15 minutes
Servings: 1 ¼ cup sauce
Calories: 89kcal
Author: Dolly (Dash for Dinner)

Ingredients

  • 1 cup granulated sugar
  • ½ cup + 1 tablespoon water
  • 6 tablespoons white vinegar
  • 4 ½ teaspoons red wine vinegar
  • 1 teaspoon finely grated onion using a small holed grater or garlic press
  • 1 tablespoon dijon mustard
  • ¼ tsp. Sesame oil
  • 1 tablespoon cornstarch
  • 1 tablespoon dried minced onion
  • 2 tsp. Dry mustard powder
  • 1 tsp. salt
  • ¾ tsp. Poppy seeds
  • ½ tsp. Celery seed
  • ¼ tsp. Onion powder
  • ¼ tsp. Paprika heaping
  • ¼ tsp. Ground black pepper heaping
  • teaspoon garlic powder heaping

Instructions

  • Whisk all of the ingredients together in a small saucepan.
  • Bring to a boil over medium-high heat, whisking often to prevent burning.
  • Reduce the heat to low and simmer until thickened, about 5 minutes. Ensure to whisk frequently.
  • Allow to cool completely, then transfer to an airtight container and label.
  • Store in the refrigerator and use within 4 weeks, or freeze for longer storage.

Video

Notes

Grated Onion:
Use a rasp grater to grate the onion. Alternatively, you can use a garlic press to press the onion.
For Low Carb/Keto/Diabetic:
Use 1 cup of sweetener that measures cup for cup with sugar instead of the white granulated sugar in this recipe.
Storage:
If you purchase a squeeze bottle for your sweet onion sauce, be sure to purchase one for a large enough opening for the larger pieces of dried minced onion to get through. You can also cut off a portion of the tip to make the opening larger.
Keep your sweet onion sauce in the fridge in an airtight container for up to 4 weeks.
Adapted from this recipe from Food.com.

Nutrition

Serving: 1g | Calories: 89kcal | Carbohydrates: 21g | Sodium: 274mg | Sugar: 20g