This homemade Subway Sweet Onion Sauce is a reverse-engineered condiment that replicates the chain's signature sweet-and-tangy dressing. It's made by whisking sugar, vinegars, onion flakes, and spices, then simmering until thickened.
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WHISK sauce ingredients together in a small saucepan (1 cup plus 2 tablespoons granulated sugar, 1/2 cup plus 1 tablespoon cold water, 6 tablespoons white vinegar, 1 1/2 tablespoons red wine vinegar, 1 tablespoon arrowroot powder, 1 tablespoon minced onion flakes, 2 1/2 teaspoons Dijon mustard, 2 1/2 teaspoons mustard powder, 3/4 teaspoon celery salt, 3/4 teaspoon fresh onion juice, 3/4 teaspoon poppy seeds, 1/2 teaspoon onion salt, 3/8 teaspoon garlic salt, 3/8 teaspoon paprika, 3/8 teaspoon black pepper, 1-2 drops sesame oil).
BRING mixture to a boiling while whisking constantly.
REDUCE heat to low simmer, stirring until thickened and flavorful, about 5 minutes.
ALLOW to cool, then refrigerate in a sealed container (keeps indefinitely).
SERVE as a dressing for sandwiches or salads and enjoy!
Refrigerate in a sealed container indefinitely. No reheating needed; use straight from the fridge as a cold dressing or condiment.
small saucepan · whisk
It keeps indefinitely when refrigerated in a sealed container.
Yes, cornstarch works as a 1:1 substitute for thickening, though arrowroot is preferred for a clearer finish.
You can substitute with an additional 1/2 teaspoon of minced onion flakes or 1/4 teaspoon onion powder, though fresh juice provides the best flavor.
No; this recipe relies on 1 cup plus 2 tablespoons granulated sugar for its signature sweetness and cannot be easily modified for low-sugar use.
It should thicken to a pourable, glossy consistency after about 5 minutes on low heat, similar to a light salad dressing.
