Here, we put all the components of a classic shrimp boil into foil packets for cute, individually portioned meals. Be sure to choose extra-large, shell-on shrimp, which stay plump and juicy during the 15 to 20 minutes on the grill.
Preheat grill to medium-high. Cut four 12-inch lengths of heavy-duty foil.
Divide potatoes, corn, shrimp, sausage and garlic among the foil pieces. Drizzle with oil and sprinkle with Old Bay. Gently toss to coat. Top each with a lemon wedge. Gather the long edges of the foil and crimp, then fold up the ends to make packets.
Grill the packets until the potatoes are tender and the shrimp are pink, 15 to 20 minutes. Serve with melted butter and garnish with scallion, if desired.