Nearly a month after its June 23 opening, Shake Shack at The Shops at Stonefield still has lines stretching out the door—and, on some days, down the block. The burger chain, which got its start in 2004 as a humble hot dog cart in New York City’s Madison Square Park, has built a cult following around its smash burgers and signature $6 milkshakes. Those shakes are made with a secret frozen custard recipe, while the burgers feature a proprietary beef blend developed specifically for their flavor and texture. Is your mouth watering yet? Get in line.