Mastering these four sauce-thickening methods—roux, cornstarch slurry, beurre manié, and heavy cream—can elevate your cooking from average to exceptional. Each technique has its ideal use, and knowing when and how to apply them makes all the difference in the kitchen. Next time your sauce or gravy is looking a little thin, reach for one of these tried-and-true methods and turn it into a showstopper.