Thickening with a Cornstarch Slurry

Stir one tablespoon of cornstarch into two tablespoons of cold water until smooth. Pour it into a simmering sauce while stirring, and it thickens within a minute, turning glossy and clear. That's the shine on a stir-fry sauce or a teriyaki glaze. Add a little at a time. It needs to reach a boil to work, but long boiling or freezing makes it thin out again. Potato starch and arrowroot work the same way and give an even clearer sauce. Never add dry starch straight into hot liquid, or it lumps.