Homemade Sweet Onion Sauce

Ingredients for Homemade Sweet Onion Sauce

To make this flavor-packed sweet onion sauce, you’ll need a combination of simple yet essential ingredients that bring out the perfect balance of sweetness, tanginess, and subtle spice.

Essential Ingredients:

• 2/3 cup granulated sugar – Adds the signature sweetness that balances the tangy and savory elements.
• 1/2 cup cold water – Helps dissolve the ingredients and create the perfect sauce consistency.
• 6 tbsp white or distilled vinegar – Brings in acidity, enhancing the overall flavor profile.
• 1 tbsp cornstarch (or arrowroot powder) – Thickens the sauce, giving it a smooth texture.
• 1 tbsp minced onion flakes – Intensifies the onion flavor, adding depth.
• 2 1/2 tsp Dijon mustard – Adds a tangy kick and smooth texture.
• 2 1/2 tsp mustard powder – Boosts the complexity of the mustard flavor.
• 3/4 tsp celery salt – Provides a slightly herby and salty undertone.
• 3/4 tsp fresh onion juice – Extracted using a garlic press, this enhances the onion essence.
• 1 tsp poppy seeds – Adds a slight crunch and a hint of nuttiness.
• 1/2 tsp onion powder – Strengthens the onion taste, making the flavor bolder.
• 1/4 tsp garlic powder – A mild garlic note for extra depth.
• 1/2 tsp salt – Balances all the flavors perfectly.
• 1/3 tsp paprika – Adds warmth and a subtle smokiness.
• 1/4 tsp black pepper – Provides a mild heat to enhance the sauce.
• 1-2 drops sesame oil – A secret ingredient that rounds out the sauce with a hint of nuttiness.

How to Make Sweet Onion Sauce

This homemade Subway-style sweet onion sauce comes together in just a few simple steps. Follow these instructions for a perfectly thick, flavorful, and versatile sauce.

Step 1: Combine the Ingredients

In a small saucepan, add the sugar, cold water, vinegar, cornstarch, minced onion flakes, Dijon mustard, mustard powder, celery salt, and fresh onion juice. Whisk everything together until well combined and smooth.

Step 2: Heat the Mixture

Place the saucepan over medium-high heat and start stirring constantly. As the mixture begins to warm up, it will start thickening due to the cornstarch. Keep whisking to prevent lumps from forming.

Step 3: Add the Seasonings

Once the sauce starts to bubble slightly, lower the heat to medium-low. Stir in the poppy seeds, onion powder, garlic powder, salt, paprika, black pepper, and sesame oil. Mix everything thoroughly to ensure the flavors are well distributed.

Step 4: Simmer Until Thickened

Let the sauce simmer for about 5 minutes, stirring frequently. The sauce should reach a glossy, slightly thick consistency. If it gets too thick, add a small splash of water and stir.

Step 5: Cool and Store

Remove the saucepan from heat and allow the sauce to cool slightly. Transfer it to a clean jar or airtight container, then refrigerate overnight for the best flavor development.

Step 6: Ready to Use!

Once chilled, your homemade sweet onion sauce is ready to be drizzled over sandwiches, wraps, salads, or grilled meats. Enjoy the perfect balance of sweet, tangy, and savory flavors in every bite!

How Long to Cook Sweet Onion Sauce

The cooking time for this homemade sweet onion sauce is quite short, but it’s essential to get the right consistency and depth of flavor. Here’s a breakdown of how long each stage should take:

• Mixing the Ingredients: 2 minutes
• Heating and Stirring Until Thickened: 5 minutes
• Simmering on Low Heat for Flavor Development: 3-5 minutes
• Cooling Before Storing: 10 minutes

Total active cooking time is around 10 minutes, making this a quick and easy sauce to prepare.

How to Store Sweet Onion Sauce

Proper storage ensures your sauce remains fresh and flavorful for as long as possible. Here’s the best way to store it:

Refrigeration

• Store the sauce in a sealed jar or airtight container in the refrigerator.
• It keeps indefinitely when stored properly, thanks to the vinegar and sugar acting as natural preservatives.
• For best flavor, let the sauce rest overnight before using it.

Freezing (Not Recommended)

• This sauce is best kept in the fridge rather than frozen, as freezing can alter its texture.
• If needed, you can freeze small portions, but they may require whisking after thawing to restore consistency.

Tips for the Perfect Sweet Onion Sauce

To ensure your sauce turns out just like the Subway version (or even better!), follow these helpful tips:

✔ Use Fresh Onion Juice – The key to the sauce’s bold flavor is freshly extracted onion juice. A garlic press works perfectly to squeeze out just the right amount.

✔ Whisk Constantly – Since cornstarch is used as a thickener, it’s essential to whisk the sauce as it heats to prevent lumps from forming.

✔ Simmer, Don’t Boil – Boiling can break down the ingredients too quickly and may lead to a too-thick or overcooked sauce. Keep it on a gentle simmer to maintain the right texture.

✔ Let it Rest – For the most authentic flavor, refrigerate the sauce overnight before using. This allows the ingredients to meld together beautifully.

✔ Adjust Thickness If Needed – If your sauce becomes too thick, add a teaspoon of water at a time and whisk until it reaches your desired consistency.

Ways to Use Sweet Onion Sauce

This sauce isn’t just for sandwiches! Here are some creative ways to enjoy it:

🥪 Drizzle on Sandwiches & Wraps – Perfect for recreating your favorite Subway-inspired subs at home.

🥗 As a Salad Dressing – Thin it out slightly with a little water and toss it into fresh greens.

🍗 Over Grilled Meats – Works great as a glaze for chicken, beef, or turkey.

🍟 Dip for Fries & Snacks – A unique twist on classic dipping sauces.

🌮 Topping for Tacos & Burritos – Adds a slightly sweet contrast to savory fillings.

Once you make this homemade sweet onion sauce, you’ll always want to keep a jar in your fridge!

Homemade Sweet Onion Sauce

---

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

No reviews

• Author: Lena Meeli
• Total Time: 15 minutes
• Yield: About 1 cup of sauce 1x

Print Recipe

Pin Recipe

Description

This Homemade Sweet Onion Sauce is a perfect balance of sweet, tangy, and savory flavors, just like the famous Subway version! It’s an easy-to-make sauce that pairs beautifully with sandwiches, wraps, salads, grilled meats, and more. With simple ingredients and quick preparation, you can enjoy this delicious sauce anytime at home!

---

Ingredients

Scale 1x2x3x

• 2/3 cup granulated sugar
• 1/2 cup cold water
• 6 tbsp white or distilled vinegar
• 1 tbsp cornstarch (or arrowroot powder)
• 1 tbsp minced onion flakes
• 2 1/2 tsp Dijon mustard
• 2 1/2 tsp mustard powder
• 3/4 tsp celery salt
• 3/4 tsp fresh onion juice (use a garlic press)
• 1 tsp poppy seeds
• 1/2 tsp onion powder
• 1/4 tsp garlic powder
• 1/2 tsp salt
• 1/3 tsp paprika
• 1/4 tsp black pepper
• 1–2 drops sesame oil

Cook Mode Prevent your screen from going dark

---

Instructions

1️⃣ In a small saucepan, whisk together sugar, water, vinegar, cornstarch, minced onion flakes, Dijon mustard, mustard powder, celery salt, and fresh onion juice until fully combined.

2️⃣ Place the saucepan over medium-high heat and stir constantly as the mixture begins to warm up and thicken.

3️⃣ Once the sauce starts bubbling slightly, reduce the heat to medium-low. Add poppy seeds, onion powder, garlic powder, salt, paprika, black pepper, and sesame oil. Stir well.

4️⃣ Simmer for about 5 minutes, stirring frequently, until the sauce reaches a smooth and slightly thick consistency. If it becomes too thick, add a teaspoon of water and whisk until desired texture is achieved.

5️⃣ Remove from heat and allow to cool slightly before transferring the sauce to a clean jar or airtight container.

6️⃣ Refrigerate overnight for the best flavor. Serve and enjoy!

Notes

✅ For a sugar-free version, substitute sugar with honey, maple syrup, or stevia.
✅ For a spicier sauce, add a pinch of cayenne pepper or red pepper flakes.
✅ For a smoother texture, strain the sauce before storing.
✅ Refrigeration Tip: This sauce keeps indefinitely in an airtight container in the refrigerator.

• Prep Time: 5 minutes
• Cook Time: 10 minutes

Frequently Asked Questions About Sweet Onion Sauce

1. Can I make this sauce without sugar?

Yes! If you prefer a sugar-free version, you can substitute granulated sugar with honey, maple syrup, or a sugar substitute like stevia or erythritol. Keep in mind that liquid sweeteners might slightly alter the sauce’s thickness, so you may need to adjust the cornstarch to maintain the right consistency.

2. What can I use instead of cornstarch?

If you don’t have cornstarch, you can use arrowroot powder or tapioca starch as a thickening agent. Both work similarly to cornstarch but may result in a slightly different texture. If you prefer a more natural alternative, you can simmer the sauce for a longer time to reduce it naturally.

3. How can I make the sauce spicier?

If you want a little heat in your sauce, try adding a pinch of cayenne pepper, red pepper flakes, or a few drops of hot sauce. Start with a small amount and adjust to your spice preference.

4. Can I use fresh onions instead of onion flakes?

Yes! If you prefer a fresher taste, finely mince a small amount of fresh onion and sauté it in a teaspoon of oil before adding the other ingredients. This will enhance the aroma and depth of flavor while maintaining the sauce’s signature onion taste. However, using onion flakes provides a more authentic Subway-style consistency.