Preheat the grill over high heat.
Tear off 4 sheets of aluminum foil, each about 12 inches long. Spread each foil sheet out over a flat work surface. Divvy up the shrimp, garlic, sausage, corn, and potatoes evenly over the center of the foil sheets.
1-1 1/2 lb large shrimp, 2 cloves of garlic, 2 smoked Andouille sausages, 3 ears of corn cut into 3 pieces each, 1 lb red potatoes
Drizzle with olive oil and give everything a gentle stir, keeping the ingredients as 'centered' as possible.
extra virgin olive oil
Sprinkle them with Old Bay seasoning, salt, and pepper, to taste. Give everything another gentle stir.
Old Bay seasoning, salt & pepper
Top each mixture with a sprinkle of parsley, a tsp of lemon juice, and a pat of butter.
4 scant tsp lemon juice, 4 tbsp butter, chopped fresh parsley leaves
Pick a side and fold the foil over top of the mixture to completely cover the food. Roll the top and bottom edges to seal them closed. Ensure it's folded so the seal is tight.
Transfer the foil packets to the heated grill and cook until just cooked through, about 15-20 minutes, gently flipping them half way through.
Pierce each packet with a fork or a knife to allow the trapped steam to safely escape, and serve immediately.