What’s more elusive than a well‑seared steak with a rosy interior? A well-seared thin steak with a rosy interior. Even when the meat’s surface is dry and the heat is cranked—prime conditions for browning—it’s a race against time to develop a rich crust before the inside goes gray.
Behind the Recipes
Grilled Flank Steak Smarts
A dash of sugar (and some other tricks) take flank steak from good to great.
By Garth Clingingsmith
Published Apr. 2, 2024.
Using the Maillard Reaction For Better Browning
Plenty of cooking traditions boost browning by coating proteins with something sweet. Think: kalbi (Korean grilled short ribs), thit heo nuong xa (Vietnamese grilled lemongrass pork chops), and the aptly named sugar steak that’s claimed by Bastien’s Restaurant in Denver but appears in eateries and recipes across the country.
All of these came to mind as I was grilling flank steak (a quick-cooking cut that I often throw on the grill for dinner) and thinking how I’ve never managed to build up a deeply brown crust on the meat before the interior cooks through. Adding a dash of sugar to the salt I typically rub on the meat’s surface before cooking would encourage faster, deeper Maillard browning and caramelization so that the steak’s exterior and interior doneness could align. The meat wouldn’t be sweet—just bronzed.
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Four Steps to Perfect Flank Steak
A typical sugar steak is seasoned with sugar and salt twice before cooking: first about an hour ahead and then again just before the steak hits the fire.
First, I divided a steak (1½ pounds or so) into quadrants to allow the thinner portions to be pulled off the fire as soon as they were done and to shorten the steak’s muscle fibers so there would be less buckling during cooking.
Second, I rubbed each piece with a blend of 4 parts sugar to 3 parts kosher salt (a conservative amount of sugar by sugar-steak standards) and let the meat rest for an hour before applying another round of the sugar-salt mix.
Third, I grilled the steaks over a hot fire—flipping every 2 minutes to further minimize any buckling, prevent either side from overcooking, and develop nice grill marks.
Finally, When the meat hit 130 degrees, I moved it to a wire rack set in a rimmed baking sheet to rest—uncovered to avoid steaming the lovely crust. (Collagen-rich steaks such as flank are more tender when cooked to medium versus medium-rare.)
Science: A Sweet Trick for Fast Browning
Rubbing flank steak with sugar and salt twice before grilling seasons the meat and helps the thin cut brown quickly. The first coat, applied an hour before cooking, denatures the steak’s surface proteins so that they dry out and form a pellicle that develops Maillard browning and caramelizes deeply. The second, applied just before grilling, caramelizes and adds more seasoning and delicate crunch.
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The sugar treatment was a game changer: After sitting for an hour, the steak developed a pellicle that helped the last-minute sugar-salt application stick and encouraged deep Maillard browning and caramelization.
I found I could even dial back the sugar to a 1:1 ratio with the salt, and the color was just as nice. And since most of the sugar dissolved and lost some sweetness when it caramelized, the steak tasted like well-seasoned meat, not candy.
Lastly, I sliced the meat thin against the grain to maximize tenderness and finished it with butter seasoned with a savory Montreal spice blend–inspired mix—a throwback to the rub I added to steaks as a kid, which happens to perfectly complement the beefy, relatively lean flank.
