This is a versatile sauce and basic to any Filipino or Chinese kitchen. I learned how to make a basic sweet and sour sauce from my mother and adapted it as needed. You can serve this sauce with crispy wontons (like Crispy Shrimp Wontons) or lumpia rolls, dress it up with sliced onions, ginger and bell peppers for fried fish, or dilute it as a dip for chicharrones. You can make it spicier, milder, thicker, or thinner, change the top flavor note by using a different vinegar, or serve it to diabetics like me by substituting artificial sweetener for sugar.
1 C palm vinegar
1 T tomato ketchup
½ C sugar or sucralose sugar substitute
½ t red pepper flakes
¼ t salt
½ t black peppercorns
¼ C water
1 dried bay leaf
1 T cornstarch
Place the vinegar, ketchup, sugar, red pepper flakes, salt, peppercorns, bay leaf, and water in a small non-reactive sauce pan. DO NOT STIR. Over medium-high heat, bring to a boil before you stir the ingredients to mix them thoroughly. Reduce heat and simmer gently for 4-5 minutes.
Taste the sauce and adjust the flavors, if needed, to your taste. If you are embellishing the sauce in any way this is the time to do it. Remember to bring the sauce to a full boil for about 1 minute after you adjust the seasonings.
Dissolve the cornstarch in about ¼ C water. Raise the temperature to medium-high, pour the cornstarch mixture into the sauce, and bring the pot to a boil. Stir the sauce and allow to boil until it becomes translucent. Pour into a bowl or gravy boat and serve.