3Thai bird’s eye chili peppers, seeded and minced (or 2 teaspoons crushed chili pepper flakes)
Combine all the ingredients except the cornstarch in a medium-sized non-stick pan. Heat over medium-high heat and stir occasionally until bringing to a boil. Turn to medium heat. Cook and stir for 5 minutes. Turn to medium-low heat.
Mix the cornstarch with 2 tablespoons water and stir until fully dissolved. Pour into the pan with the sauce. Stir constantly until the sauce thickens enough to coat the back of a spoon, 1 minute or so. Keep in mind that the sauce will further thicken once it cools. Taste the sauce and adjust the taste by adding more sugar if not sweet enough, or more vinegar if not sour enough. If the sauce turns out too thick, mix in a few spoons of water to thin it out while it’s still hot.
Pour the sauce into a bowl and let sit until completely cooled. Serve it as a dipping sauce or store it in an airtight jar in the fridge for future use. It will keep in the fridge for about a week or in the freezer for up to 2 months.