Homemade Sweet Onion Sauce
Recreate Subway’s famous Homemade Sweet Onion Sauce with this easy copycat recipe. This delightful sauce offers the perfect blend of sweet and tangy flavors, making it an ideal addition to sandwiches, salads, and more. Whether you’re hosting a gathering or preparing a family meal, this versatile sauce elevates any dish with its unique taste profile.
Why You’ll Love This Recipe
- Quick and Easy – With just 15 minutes of total time, you can whip up this flavorful sauce in no time.
- Versatile Use – Perfect for sandwiches, salads, or as a dipping sauce, it complements various dishes beautifully.
- Homemade Goodness – Made from fresh ingredients, you control what goes into your food, ensuring quality and flavor.
- Customizable Flavor – Adjust the sweetness or tanginess to suit your palate, making it truly your own.
- Vegan-Friendly – This recipe is completely plant-based, making it suitable for vegan diets.
Tools and Preparation
Before diving into making your homemade sweet onion sauce, gather a few essential tools. Having everything ready will make the process smooth.
Essential Tools and Equipment
- Saucepan
- Whisk
- Measuring cups
- Measuring spoons
- Airtight container
Importance of Each Tool
- Saucepan – A sturdy saucepan is essential for heating the ingredients evenly without burning them.
- Whisk – A whisk allows you to mix ingredients thoroughly and achieve the desired texture.
- Measuring Cups and Spoons – Accurate measurements are crucial for achieving the perfect 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.
Main Ingredients
- 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. This includes sugar, water, white vinegar, red wine vinegar, freshly grated onion, cornstarch, Dijon mustard, mustard powder, poppy seeds, sesame oil, onion powder, salt, garlic powder, celery seed, paprika, and black pepper.
Step 2: Heat Mixture
Bring the mixture to a boil while whisking constantly. Let it boil for 5 minutes to allow the flavors to meld together.
Step 3: Simmer and Cool
Reduce heat to simmer for another 5 minutes while continuing to whisk. Once done cooking, remove from heat and allow the sauce to cool completely.
Step 4: Store Your Sauce
Transfer the cooled sauce into an airtight container. Store it in the refrigerator for up to one week for optimal freshness.
Now you have a delicious batch of homemade sweet onion sauce ready to enhance your meals! Enjoy!
How to Serve Homemade Sweet Onion Sauce
Homemade Sweet Onion Sauce is versatile and can elevate many dishes. Whether you’re making a sandwich, salad, or a dip, this sauce adds a unique flavor that everyone will love.
On Sandwiches
- Classic Sub: Drizzle on your favorite sub for a sweet and tangy kick.
- Grilled Chicken Sandwich: Pair with grilled chicken for a delicious balance of flavors.
- Veggie Wrap: Spread on a veggie wrap to enhance the fresh ingredients.
In Salads
- Mixed Greens Salad: Use as a dressing to add depth to your greens.
- Pasta Salad: Toss in pasta salad for a zesty twist.
- Coleslaw: Mix into coleslaw for an extra layer of flavor.
As a Dip
- Veggie Platter: Serve alongside fresh vegetables for a tasty dip.
- Chips and Dip: Use as a dip for tortilla chips for a unique snack.
With Grilled Meats
- Grilled Steak: Brush on grilled steak right before serving for added sweetness.
- BBQ Chicken: Glaze over BBQ chicken during the last few minutes of cooking.

How to Perfect Homemade Sweet Onion Sauce
Creating the perfect Homemade Sweet Onion Sauce requires attention to detail and some helpful tips. Follow these suggestions to elevate your sauce-making skills.
- Use Fresh Ingredients: Always opt for fresh onions and spices to ensure the best flavor.
- Adjust Sweetness: Feel free to tweak the sugar amount based on your taste preferences.
- Experiment with Vinegars: Try different types of vinegar for various flavor profiles.
- Whisk Constantly: Whisking while cooking helps achieve a smooth consistency without lumps.
- Store Properly: Keep it in an airtight container in the fridge to maintain freshness.
- Let It Sit: Allowing the sauce to sit overnight enhances the flavors even more.
Best Side Dishes for Homemade Sweet Onion Sauce
Homemade Sweet Onion Sauce pairs wonderfully with various side dishes, enhancing their flavors. Here are some great options to consider:
- French Fries: Crispy fries dipped in sweet onion sauce create a delightful contrast.
- Onion Rings: Enjoy onion rings with this sauce instead of traditional ketchup.
- Grilled Vegetables: Drizzle over grilled veggies for added flavor and moisture.
- Rice Pilaf: Stir into rice pilaf to complement its nutty flavors.
- Potato Wedges: Serve potato wedges with sweet onion sauce as an alternative dipping option.
- Quinoa Salad: Mix into quinoa salad for added sweetness and tang.
Common Mistakes to Avoid
Making Homemade Sweet Onion Sauce can be simple, but there are common pitfalls to watch out for. Here are some mistakes to avoid:
-
Using stale ingredients: Always use fresh ingredients to enhance the flavor of your sweet onion sauce. Check the expiration dates on your vinegars and spices.
-
Not whisking enough: Properly whisking the mixture while it boils is crucial for a smooth texture. Skipping this step can lead to lumps in your sauce.
-
Ignoring cooling time: Allowing the sauce to cool before storing is essential. If you store it hot, condensation will create excess moisture and dilute the flavors.
-
Overcooking the sauce: Cooking for too long can alter the taste and consistency. Stick to the recommended cooking times for optimal results.
-
Storing in non-airtight containers: Use airtight containers for storage to keep your sauce fresh longer. Non-airtight containers can lead to spoilage or flavor loss.

Storage & Reheating Instructions
Refrigerator Storage
- Store in an airtight container.
- Keeps well for up to 1 week in the refrigerator.
Freezing Homemade Sweet Onion Sauce
- Freeze in small portions using ice cube trays.
- Transfer frozen cubes to a freezer-safe bag and store for up to 3 months.
Reheating Homemade Sweet Onion Sauce
-
Oven: Preheat oven to 350°F (175°C), place sauce in an oven-safe dish, cover with foil, and heat for about 10-15 minutes.
-
Microwave: Place sauce in a microwave-safe bowl, cover loosely, and heat in 30-second intervals, stirring between each until warmed through.
-
Stovetop: Pour into a saucepan over low heat, stirring frequently until warmed throughout.
Frequently Asked Questions
Here are some commonly asked questions about making Homemade Sweet Onion Sauce:
What is Homemade Sweet Onion Sauce used for?
Homemade Sweet Onion Sauce is perfect as a sandwich spread or salad dressing. It adds a deliciously sweet and tangy flavor that enhances various dishes.
Can I customize my Homemade Sweet Onion Sauce?
Absolutely! You can adjust the sweetness or tanginess by adding more sugar or vinegar according to your taste preferences.
How do I make my Homemade Sweet Onion Sauce thicker?
To thicken your sauce, add an additional teaspoon of cornstarch mixed with water and simmer until desired thickness is reached.
Is this Homemade Sweet Onion Sauce vegan?
Yes! This recipe contains no animal products, making it suitable for vegans.
Final Thoughts
This Homemade Sweet Onion Sauce is not only easy to make but also incredibly versatile. It adds a wonderful flavor pop to sandwiches, salads, and even grilled veggies. Feel free to customize it with different herbs or spices based on your preference. Enjoy this delightful condiment with your favorite dishes!

Homemade Sweet Onion Sauce
- Total Time: 15 minutes
- Yield: About 16 servings (1 tablespoon each) 1x
Description
Elevate your meals with this easy Homemade Sweet Onion Sauce, inspired by Subway’s beloved recipe. This delightful condiment harmonizes sweet and tangy flavors, making it a versatile addition to sandwiches, salads, and dips. Whether you’re hosting a gathering or preparing a family dinner, this sauce will enhance any dish with its unique taste profile. In just 15 minutes, you can create a batch of fresh, homemade goodness that’s vegan-friendly and customizable to suit your palate.
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
- 1/2 Teaspoon Sesame Oil
- 2 Teaspoons Mustard Powder
- 1 Teaspoon Poppy Seeds
- 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: sugar, water, white vinegar, red wine vinegar, grated onion, cornstarch, Dijon mustard, mustard powder, and sesame oil.
- Heat the mixture over medium heat while whisking constantly until it boils. Allow it to boil for about 5 minutes.
- Reduce heat and let it simmer for an additional 5 minutes while continuing to whisk.
- Remove from heat and let the sauce cool completely before transferring it into an airtight container.
- Prep Time: 10 minutes
- Cook Time: 5 minutes
- Category: Condiment
- Method: Cooking
- Cuisine: American
Nutrition
- Serving Size: 1 serving
- Calories: 50
- Sugar: 12g
- Sodium: 30mg
- Fat: 0g
- Saturated Fat: 0g
- Unsaturated Fat: 0g
- Trans Fat: 0g
- Carbohydrates: 13g
- Fiber: 0g
- Protein: 0g
- Cholesterol: 0mg