Recreate Subway’s famous Homemade Sweet Onion Sauce with this easy copycat recipe. This sauce offers a delightful blend of sweet and tangy flavors, making it a perfect addition to sandwiches, salads, and even as a dip for veggies. Whether you’re hosting a gathering or simply want to elevate your meals at home, this versatile sauce is sure to impress.

Jump to:
- Why You’ll Love This Recipe
- Tools and Preparation
- Essential Tools and Equipment
- Importance of Each Tool
- Ingredients
- For the Sauce
- How to Make Homemade Sweet Onion Sauce
- Step 1: Combine Ingredients
- Step 2: Heat Mixture
- Step 3: Cool and Store
- How to Serve Homemade Sweet Onion Sauce
- With Sandwiches
- As a Salad Dressing
- For Dipping
- How to Perfect Homemade Sweet Onion Sauce
- Best Side Dishes for Homemade Sweet Onion Sauce
- Common Mistakes to Avoid
- Storage & Reheating Instructions
- Refrigerator Storage
- Freezing Homemade Sweet Onion Sauce
- Reheating Homemade Sweet Onion Sauce
- Frequently Asked Questions
- Can I adjust the sweetness of Homemade Sweet Onion Sauce?
- What dishes pair well with Homemade Sweet Onion Sauce?
- Is this Homemade Sweet Onion Sauce vegan?
- How long does Homemade Sweet Onion Sauce last?
- What can I use instead of Dijon mustard?
- Final Thoughts
- 📖 Recipe Card
Why You’ll Love This Recipe
- Easy to Make – With just a few simple ingredients, you can whip up this sauce in no time.
- Versatile Flavor – Use it on sandwiches, salads, or as a dipping sauce for your favorite snacks.
- Healthy Option – Made from fresh ingredients, it’s a healthier alternative to store-bought sauces.
- Customizable – Adjust the sweetness or tanginess to suit your personal taste preferences.
- Perfect for Meal Prep – Store it in the fridge for up to a week and enjoy it throughout the week.
Tools and Preparation
Before you start making your Homemade Sweet Onion Sauce, gather the necessary tools to ensure a smooth cooking process.
Essential Tools and Equipment
- Saucepan
- Whisk
- Measuring cups
- Measuring spoons
- Airtight container
Importance of Each Tool
- Saucepan: A sturdy saucepan is essential for evenly heating and mixing the ingredients.
- Whisk: Using a whisk helps achieve a smooth consistency by thoroughly blending all components of the sauce.
- Measuring cups: Accurate measurements are key to getting the right balance of flavors in your sauce.
Ingredients
Recreate Subway’s famous sweet onion sauce with this easy copycat recipe. Perfect blend of sweet and tangy flavors.
For the Sauce
- 1 Cup Sugar
- 1/2 Cup Water
- 6 Tablespoons White Vinegar
- 1 1/2 Tablespoons Red Wine Vinegar
- 1/2 Tablespoon Onion, freshly grated
- 1 Tablespoon Cornstarch
- 2 Teaspoons Dijon Mustard
- 2 Teaspoons Mustard Powder
- 1 Teaspoon Poppy Seeds
- 1/2 Teaspoon Sesame Oil
- 1/2 Teaspoon Onion Powder
- 1/2 Teaspoon Salt
- 1/4 Teaspoon Garlic Powder
- 1/4 Teaspoon Celery Seed
- 1/4 Teaspoon Paprika
- 1/4 Teaspoon Black Pepper
How to Make Homemade Sweet Onion Sauce
Step 1: Combine Ingredients
Add all ingredients to a saucepan. Ensure the grater onion is well-distributed throughout the mixture.
Step 2: Heat Mixture
Bring the mixture to a boil while whisking constantly. Allow it to boil for 5 minutes. Then reduce heat and let it simmer for another 5 minutes, continuing to whisk continuously.
Step 3: Cool and Store
Remove from heat and allow the sauce to cool completely. Once cooled, store in an airtight container in the refrigerator for up to one week.
Enjoy your delicious Homemade Sweet Onion Sauce on sandwiches, salads, or as a marinade!
How to Serve Homemade Sweet Onion Sauce
Homemade Sweet Onion Sauce is a versatile condiment that enhances various dishes. Whether you’re making sandwiches, wraps, or salads, this sauce adds a delightful sweet and tangy flavor that everyone will love.
With Sandwiches
- Classic Sub: Drizzle this sauce over your favorite sub for a delicious twist.
- Grilled Chicken Sandwich: Pair with grilled chicken and fresh veggies for a hearty meal.
- Veggie Wrap: Add to a wrap filled with fresh greens and roasted vegetables for a tasty lunch.
As a Salad Dressing
- Mixed Greens: Toss with mixed greens for an easy salad dressing.
- Coleslaw: Use it as a creamy base in coleslaw for added flavor.
- Pasta Salad: Mix in with pasta salad for a unique dressing option.
For Dipping
- Vegetable Platter: Serve as a dip for fresh veggies at your next gathering.
- Chicken Nuggets: Use it as a dipping sauce for chicken nuggets or tenders.
- Fries: Dip crispy fries into the sauce for an unexpected treat.

How to Perfect Homemade Sweet Onion Sauce
To ensure your Homemade Sweet Onion Sauce turns out perfectly every time, follow these helpful tips.
- Adjust Sweetness: If you prefer it sweeter, add more sugar gradually until desired taste is reached.
- Vinegar Balance: Experiment with different vinegar ratios to find the perfect tanginess for your palate.
- Fresh Grating: Use freshly grated onion for the best flavor; pre-packaged may lack freshness.
- Storage Matters: Keep the sauce in an airtight container in the fridge to maintain its quality longer.
- Whisk Constantly: Stirring continuously while boiling prevents burning and ensures even consistency.
Best Side Dishes for Homemade Sweet Onion Sauce
Pairing side dishes with your Homemade Sweet Onion Sauce can elevate your meal experience. Here are some great options to consider.
- Sweet Potato Fries: These crispy bites provide a sweet contrast that complements the sauce beautifully.
- Garden Salad: A fresh garden salad dressed lightly allows the flavors of the sauce to shine through.
- Corn on the Cob: Grilled corn drizzled with this sauce offers a delightful taste combination.
- Potato Wedges: Seasoned potato wedges pair well, providing crunch and flavor alongside the sauce.
- Onion Rings: Deep-fried onion rings make an excellent pairing, enhancing the onion flavor theme.
- Roasted Vegetables: Seasoned roasted veggies bring earthiness that balances the sweetness of the sauce.
Common Mistakes to Avoid
Creating your own Homemade Sweet Onion Sauce can be a delightful experience, but there are a few pitfalls to watch out for.
- Skipping the Whisking: It’s essential to whisk constantly while boiling. This prevents lumps and ensures a smooth texture.
- Using Old Ingredients: Fresh ingredients make a difference. Check the expiration dates on your vinegar and spices for optimal flavor.
- Not Cooling Properly: Allow the sauce to cool completely before storing. This helps maintain its consistency and flavor over time.
- Ignoring Storage Guidelines: Use airtight containers to store your sauce. This keeps it fresh for longer and prevents contamination.
- Overcooking the Sauce: Cooking too long can alter the taste. Stick to the recommended cooking times for best results.

Storage & Reheating Instructions
Refrigerator Storage
- Store in an airtight container.
- The sauce lasts up to 1 week in the refrigerator.
Freezing Homemade Sweet Onion Sauce
- Use freezer-safe containers or bags.
- Homemade Sweet Onion Sauce can be frozen for up to 3 months.
Reheating Homemade Sweet Onion Sauce
- Oven: Preheat to 350°F, place in an oven-safe dish, cover with foil, and heat for about 10-15 minutes.
- Microwave: Heat in short bursts of 30 seconds, stirring in between until warmed through.
- Stovetop: Place in a saucepan over low heat, stirring frequently until hot.
Frequently Asked Questions
Here are some common questions about making your own Homemade Sweet Onion Sauce.
Can I adjust the sweetness of Homemade Sweet Onion Sauce?
Yes! You can add more sugar or reduce it according to your taste preferences.
What dishes pair well with Homemade Sweet Onion Sauce?
This sauce is great as a sandwich spread, salad dressing, or marinade. It adds flavor to wraps and grilled meats too!
Is this Homemade Sweet Onion Sauce vegan?
Absolutely! All ingredients used in this recipe are plant-based, making it a great vegan option.
How long does Homemade Sweet Onion Sauce last?
In the refrigerator, it stays fresh for up to one week. For longer storage, consider freezing it.
What can I use instead of Dijon mustard?
You can substitute with yellow mustard or omit it entirely if you prefer a milder sauce flavor.
Final Thoughts
This Homemade Sweet Onion Sauce is not only easy to make but also incredibly versatile. It can enhance a variety of dishes from sandwiches to salads. Don’t hesitate to customize it by adjusting the sweetness or adding spices that suit your taste. Enjoy making this delicious sauce!
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Homemade Sweet Onion Sauce
- Total Time: 20 minutes
- Yield: Approximately 12 servings 1x
Description
Recreate the beloved Homemade Sweet Onion Sauce you know from Subway with this quick and easy copycat recipe. This sauce combines a delightful mix of sweet and tangy flavors, making it an ideal condiment for sandwiches, salads, or as a dip for fresh veggies. It’s the perfect way to elevate your meals at home or impress guests during gatherings. With just a handful of simple ingredients and straightforward steps, you’ll have a delicious sauce ready in no time. Enjoy this versatile addition that can be customized to suit your taste preferences!
Ingredients
- 1 Cup Sugar
- 1/2 Cup Water
- 6 Tablespoons White Vinegar
- 1 1/2 Tablespoons Red Wine Vinegar
- 1/2 Tablespoon Freshly Grated Onion
- 1 Tablespoon Cornstarch
- 2 Teaspoons Dijon Mustard
- 2 Teaspoons Mustard Powder
- 1 Teaspoon Poppy Seeds
- 1/2 Teaspoon Sesame Oil
- 1/2 Teaspoon Onion Powder
- 1/2 Teaspoon Salt
- 1/4 Teaspoon Garlic Powder
- 1/4 Teaspoon Celery Seed
- 1/4 Teaspoon Paprika
- 1/4 Teaspoon Black Pepper
Instructions
- In a saucepan, combine all ingredients and ensure the grated onion is evenly mixed.
- Bring the mixture to a boil over medium heat while whisking continuously. Boil for 5 minutes.
- Reduce heat and let it simmer for an additional 5 minutes, continuing to stir.
- Remove from heat and allow the sauce to cool completely before transferring it to an airtight container.
- Prep Time: 10 minutes
- Cook Time: 10 minutes
- Category: Condiment
- Method: Stovetop
- Cuisine: American
Nutrition
- Serving Size: 30g
- Calories: 80
- Sugar: 17g
- Sodium: 140mg
- Fat: 0g
- Saturated Fat: 0g
- Unsaturated Fat: 0g
- Trans Fat: 0g
- Carbohydrates: 21g
- Fiber: 0g
- Protein: <1g
- Cholesterol: 0mg