Subway Sweet Onion Sauce

Name: Subway Sweet Onion Sauce
Prep time: 5 min
Cook time: 10 min
Total time: 15 min
Cuisine: American
Ingredients: ½ cup (120ml) cold water; 6 tbsp white vinegar; 2 tbsp red wine vinegar; 1 drop sesame oil (up to 2 drops); 2½ tsp Dijon mustard; ¾ tsp fresh onion juice (use a garlic press); 1 cup (200g) granulated sugar; 1 tbsp arrowroot; 1 tbsp minced onion flakes; 2½ tsp mustard powder; ½ tsp celery seed; 1 tsp poppy seed; 1 tsp salt; ¼ tsp garlic salt (plus 1/8 teaspoon); ¼ tsp paprika (plus 1/8 teaspoon); ¼ tsp black pepper