Place all of the ingredients into a small saucepan.
Whisk until everything is combined, make sure the cornstarch has fully dissolved and is smooth.
Place on the stove over medium heat.
Heat until all of the sugar has dissolved. You’ll know if you stir it and don’t feel anything grainy along the bottom of the pan.
After sugar has dissolved, continue simmering until the sauce has thickened enough to coat a spoon (dip spoon in the sauce, pull it out and if it’s finished, the sauce should still be coating the spoon).
Store in an airtight jar/container for a few days to a week.