From America's Test Kitchen Season 12: Here's the Beef
Few things are as satisfying as a thick, juicy pub-style burger. But avoiding the usual gray band of overcooked meat is a challenge. We wanted a patty that was well-seared, juicy, and evenly rosy from center to edge. Grinding our own meat in the food processor was a must, and sirloin steak tips were the right cut for the job. Cutting the meat into small 1/2-inch chunks before grinding and lightly packing the meat to form patties gave the burgers just enough structure to hold their shape in the skillet. A little melted butter improved their flavor and juiciness, but our biggest discovery came when we transferred the burgers from the stovetop to the oven to finish cooking—the stovetop provided intense heat for searing, while the oven’s gentle ambient heat allowed for even cooking, thus eliminating the overcooked gray zone.
Sirloin steak tips are also sold as flap meat. When stirring the butter and pepper into the ground meat and shaping the patties, take care not to overwork the meat or the burgers will become dense.