Hamburgers are easily one of America’s most popular foods and the true test of a grill cook. A great grilled burger is well browned on the exterior and juicy and tender on the inside. But they rarely turn out that way. More likely, they are gray, tough, and bland. We wanted to make the ultimate no-holds-barred burger. Here’s what we discovered:

Test Kitchen Discoveries

Make a “panade”—a blend of breadcrumbs and milk—to bind the burgers together.

Add bacon fat to the beef mixture. The rich, smoky-tasting fat adds flavor and will keep the meat moist.

A little minced garlic goes far in flavoring the meat.

Be gentle with the beef mixture while mixing and shaping the burgers. Overworking will yield tough, dense burgers.

For this recipe, you want ground beef that is 85 percent to 90 percent lean. With the added bacon fat, 80 percent lean beef will make slightly greasy burgers. Crumble the cooked bacon slices over a salad, or use the slices as a burger topping.

Flank steaks smaller or larger than 2 pounds can be used, but adjust the amount of salt and pepper accordingly. We prefer flank steak cooked rare or medium-rare. If the steak is to retain its juices, it must be allowed to rest before being sliced. If using a gas grill, cook the steak over high heat, following the times in step 3, but keep the cover down. If the meat is significantly underdone when tested with a paring knife, turn off one burner and position the steak so that the thinner side is over the cool part of the grill and the thicker side is over the hot part of the grill.