Popsugar Lifestyle Grilling Grilling Life Hacks 15 Grilling Hacks to Bust Out in Your Backyard 22 May, 2018 by Anna Monette Roberts View On One Page Photo 2 of 15 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 2 Season burger patties with mustard on one side. Here's a little-known secret you can try at home: In-n-Out spreads mustard on the top of the patties before flipping them. The flavor and sear the mustard renders will become your new favorite burger hack. Previous Next Start Slideshow GrillingSpringCooking TipsCooking How-ToSummer