In a small bowl or saucepan, mix all of the ingredients together (except for the cornstarch slurry).Set the saucepan on medium-high heat and bring the mixture to a boil. Then, reduce the heat to a low simmer.
Make the cornstarch slurry by stirring together the cornstarch and water. Stir it into the mixture and stir frequently until the sauce slightly thickens, about 3 minutes. Remove from heat.
Serve immediately or store in an airtight container in the refrigerator for up to 2 weeks.