In a small saucepan, mix sugar, 3/4 cup water, and apple cider vinegar. Stirring occasionally, heat the mixture to dissolve the sugar. After boiling, add chili flakes, garlic powder, and onion powder. Blend.

In a small dish, dissolve the cornstarch in 1/4 cup lukewarm water. Mix the cornstarch mixture in the pot. Stir the sauce on medium-high heat until it boils. After the sauce boils, lower the heat and simmer for 2-3 minutes until it thickens.

Cool the sauce to room temperature. Cooling will thicken the sauce. After cooling, put the sauce to a clean jar with a tight lid. Refrigerated sauce lasts 2 weeks.