This Subway Sweet Onion Sauce Recipe is a delightful way to elevate your sandwiches and salads. In just 15 minutes, you can create this sweet and tangy sauce that’s not only vegan and gluten-free but also oil-free. Perfect for any occasion, this sauce brings a burst of flavor that pairs well with various dishes, making it a versatile addition to your culinary arsenal.
Why You’ll Love This Recipe
- Quick Preparation: You can whip up this delicious sauce in just 15 minutes, making it an ideal choice for last-minute meals.
- Versatile Use: This sauce enhances the flavor of sandwiches, salads, and wraps, giving them a gourmet touch.
- Healthy Alternative: With no oils or preservatives, this sauce is a healthier option than many store-bought versions.
- Easy to Customize: Adjust the sweetness or tanginess to fit your taste preferences by modifying the sugar or vinegar amounts.
- Crowd-Pleaser: Whether it’s a family dinner or a barbecue, this sauce will impress your guests with its unique flavor.
Tools and Preparation
To make the Subway Sweet Onion Sauce Recipe efficiently, you’ll need some essential kitchen tools. Having the right equipment on hand will make the preparation smoother and faster.
Essential Tools and Equipment
- Blender
- Muslin cloth or fine strainer
- Saucepan
- Whisk
- Airtight container
Importance of Each Tool
- Blender: Essential for achieving a smooth consistency by blending onions and garlic effortlessly.
- Muslin cloth or fine strainer: Helps extract juice without any solid bits, ensuring a silky-smooth sauce.
- Saucepan: Necessary for cooking the ingredients together evenly while allowing for easy stirring.
Ingredients
Subway copycat sweet onion sauce recipe at home from scratch within 15 minutes. An easy, vegan, gluten-free, oil-free recipe.
For the Sauce:
- 1 medium-size onion
- 2 garlic cloves
- ¾ cup water plus ¼ cup water
- ⅓ cup granulated sugar
- 1 tsp balsamic vinegar
- 1 tsp white vinegar
- ¼ tsp nigella seeds/kalonji
- ¼ tsp black pepper, freshly ground (or to taste)
- ¼ tsp salt (or to taste)
- 2 tsp cornflour/cornstarch
- ½ tsp lemon juice, fresh
How to Make Subway Sweet Onion Sauce Recipe
Step 1: Prepare the Onion and Garlic
- Peel the onion and garlic, then roughly chop them.
- Blend until smooth.
- Squeeze the juice using a muslin cloth and transfer it to a pan or pot.
Step 2: Cook the Mixture
- Heat the saucepan over medium heat.
- Add in ¾ cup water, sugar, salt, white vinegar, balsamic vinegar, black pepper, and nigella seeds.
- Bring the mixture to a boil until the sugar dissolves completely.
Step 3: Make the Slurry
- In a separate bowl, whisk together ¼ cup water and cornflour/cornstarch until you have a smooth slurry.
Step 4: Thicken the Sauce
- Slowly add the cornflour slurry to the pan while stirring continuously over medium flame.
- Stir until the sauce thickens and becomes glossy.
Step 5: Final Touches
- Remove from heat and stir in ½ tsp lemon juice. Mix well to combine.
- Allow the sauce to cool to room temperature before transferring it to an airtight container.
Storage Instructions
Store your Subway Sweet Onion Sauce in an airtight container in the refrigerator for optimal freshness. Enjoy it whenever you want that sweet onion flavor!
How to Serve Subway Sweet Onion Sauce Recipe
Subway Sweet Onion Sauce is a versatile condiment that adds a delightful flavor to various dishes. Whether you’re making a sandwich, salad, or something unique, this sauce can elevate your meal.
Sandwiches
- Submarine Sandwiches: Use the sauce generously in your favorite sub for added sweetness and depth.
- Wraps: Drizzle over wraps filled with veggies and protein for a tasty twist.
Salads
- Green Salads: Toss it with mixed greens and vegetables for a refreshing salad dressing.
- Grain Bowls: Add to grain bowls for a burst of flavor that complements grains like quinoa or rice.
Dips
- Veggie Dip: Serve as a dipping sauce alongside fresh cut vegetables for a healthy snack.
- Chips Dip: Pair with tortilla chips for a sweet and savory appetizer.
Marinades
- Tofu or Tempeh Marinade: Use the sauce as a marinade for tofu or tempeh before grilling or baking.
- Chicken Marinade: Marinate chicken pieces in this sauce for an easy flavor infusion.

How to Perfect Subway Sweet Onion Sauce Recipe
To achieve the perfect Subway Sweet Onion Sauce, keep these tips in mind. Each step can enhance the flavors and texture of your sauce.
- Fresh Ingredients: Always use fresh onions and garlic for the best taste and aroma.
- Adjust Sweetness: Feel free to tweak the sugar amount based on your sweetness preference.
- Whisk Well: Ensure you whisk the cornflour slurry thoroughly to avoid lumps in your sauce.
- Taste as You Go: Sample the sauce during cooking to adjust seasoning to suit your palate.
- Cool Properly: Allow the sauce to cool completely before storing it in an airtight container for optimal freshness.
Best Side Dishes for Subway Sweet Onion Sauce Recipe
Pairing side dishes with your Subway Sweet Onion Sauce can enhance your dining experience. Here are some delicious options that complement this flavorful condiment.
- Vegetable Stir-Fry: A colorful mix of veggies sautéed until tender, perfect for drizzling with sweet onion sauce.
- Roasted Potatoes: Crispy roasted potatoes seasoned simply, allowing the sauce’s sweetness to shine through.
- Quinoa Salad: A light quinoa salad mixed with cucumbers and tomatoes; add sweet onion sauce as dressing.
- Grilled Veggies: Seasonal vegetables grilled to perfection; serve with a side of sweet onion sauce for dipping.
- Pita Chips: Crunchy pita chips serve as a great vehicle for enjoying this delicious sauce.
- Rice Pilaf: Fluffy rice pilaf infused with herbs pairs wonderfully when topped with sweet onion sauce.
Common Mistakes to Avoid
When making the Subway sweet onion sauce at home, it’s easy to make some common mistakes. Here are a few to keep in mind.
- Boldly measuring ingredients: Always measure your ingredients accurately. Too much sugar can make the sauce overly sweet, while too little can result in a bland flavor.
- Ignoring blending time: Make sure to blend the onion and garlic until smooth. A chunky mixture will not give you the desired consistency for the sauce.
- Neglecting temperature control: Keep an eye on the heat while cooking. Cooking on too high a flame can burn the sauce, altering its taste.
- Skipping the cornflour slurry: Don’t forget to prepare the cornflour slurry properly. This step is crucial for achieving that glossy texture.
- Not adjusting seasoning: Always taste your sauce before finishing it. Adjust salt and pepper levels according to your preference for the best flavor.
Storage & Reheating Instructions
Refrigerator Storage
- Store in an airtight container.
- The sauce will last for up to 1 week in the refrigerator.
Freezing Subway Sweet Onion Sauce Recipe
- Use freezer-safe containers for storage.
- The sauce can be frozen for up to 3 months.
Reheating Subway Sweet Onion Sauce Recipe
- Oven: Preheat your oven to 350°F (175°C), place the sauce in an oven-safe dish, and heat for about 10-15 minutes.
- Microwave: Place in a microwave-safe bowl, cover loosely, and heat in 30-second intervals, stirring between each until warm.
- Stovetop: Pour into a saucepan over low heat, stirring frequently until heated through.
Frequently Asked Questions
Here are some frequently asked questions about this delightful recipe.
Can I adjust the sweetness in the Subway Sweet Onion Sauce Recipe?
Yes, you can decrease or increase the amount of sugar based on your taste preferences.
Is this Subway Sweet Onion Sauce Recipe vegan?
Absolutely! This recipe is completely vegan and gluten-free, making it suitable for various dietary needs.
How long does it take to make Subway Sweet Onion Sauce?
The total time needed is just 15 minutes—5 minutes of prep and 10 minutes of cooking!
What dishes pair well with Subway Sweet Onion Sauce Recipe?
This versatile sauce complements sandwiches, salads, and wraps beautifully!
Final Thoughts
The Subway sweet onion sauce recipe is not only easy to make but also incredibly versatile. It enhances various dishes with its sweet and tangy flavor. Feel free to customize it by adjusting spices or using different types of vinegar! Give this recipe a try; you won’t be disappointed!

Subway Sweet Onion Sauce
- Total Time: 15 minutes
- Yield: About 8 servings 1x
Description
Elevate your meals with this Subway Sweet Onion Sauce Recipe, a quick and easy condiment that transforms sandwiches, salads, and wraps into gourmet delights. In just 15 minutes, you can whip up a sweet and tangy sauce that is not only vegan and gluten-free but also oil-free. This homemade creation is a healthier alternative to store-bought sauces, allowing you to customize the flavors to suit your taste. Perfect for any occasion, this versatile sauce adds a burst of flavor to any dish, whether you’re hosting a barbecue or preparing a simple family dinner.
Ingredients
- 1 medium-size onion
- 2 garlic cloves
- 1 cup water (divided)
- ⅓ cup granulated sugar
- 1 tsp balsamic vinegar
- 1 tsp white vinegar
- ¼ tsp nigella seeds/kalonji
- ¼ tsp black pepper (to taste)
- ¼ tsp salt (to taste)
- 2 tsp cornflour/cornstarch
- ½ tsp fresh lemon juice
Instructions
- Peel and roughly chop the onion and garlic. Blend until smooth. Strain through a muslin cloth to extract juice.
- In a saucepan over medium heat, combine the extracted juice with ¾ cup water, sugar, salt, white vinegar, balsamic vinegar, black pepper, and nigella seeds. Bring to a boil until the sugar dissolves.
- In a separate bowl, whisk together the remaining ¼ cup water and cornflour until smooth. Gradually add it to the saucepan while stirring continuously until thickened.
- Remove from heat and stir in lemon juice. Let cool before transferring to an airtight container.
- Prep Time: 5 minutes
- Cook Time: 10 minutes
- Category: Condiment
- Method: Sauce Making
- Cuisine: American
Nutrition
- Serving Size: 2 tablespoons (30g)
- Calories: 65
- Sugar: 16g
- Sodium: 80mg
- Fat: 0g
- Saturated Fat: 0g
- Unsaturated Fat: 0g
- Trans Fat: 0g
- Carbohydrates: 17g
- Fiber: 0g
- Protein: <1g
- Cholesterol: 0mg
Keywords: Use fresh ingredients for the best flavor. Adjust sweetness by varying sugar levels. Allow the sauce to cool completely before storing in the refrigerator.