This Vietnamese-inspired dish is centered upon a vibrantly flavorful mixture of chicken and aromatics, served warm on individual romaine lettuce leaves. It's a bit messy to eat, but the great taste makes it all worthwhile. Try making this with ground pork for a change of pace - or for a more complex flavor, try it with 1 pound of ground pork and 1/2 pound (8 ounces) of raw shrimp. The romaine leaves make a perfect wrapper for the meat because they naturally fold in half lengthwise along the central rib.
Remove the outer 3 or 4 layers of leaves from the lemongrass until you reach the soft, tender heart. Cut off the top two-thirds of the stalk, reserving only the bottom 6 inches (from the stem end). Finely mince the lemongrass.
Heat the oil in a large skillet over medium-high heat and add the chicken. Cook, stirring frequently, for 3 minutes, then add the ginger, lemongrass, jalapeño, fish sauce, sugar, garlic, and the lime zest and juice. Cook, stirring frequently, until the mixture is cooked through and the juices have almost evaporated, about 7 minutes. Remove the pan from the heat and stir in the mint and cilantro.
Arrange the romaine leaves on a platter. Transfer the chicken mixture to a bowl. To serve, top a lettuce leaf with some of the chicken, arranging it along the central rib, but stopping a half inch short of either end. Fold the leaf in half lengthwise, and enjoy!