Preheat your grill to medium-high heat (375°F) or your oven to 400°F.

In a large mixing bowl, combine shrimp, sliced sausage, cubed potatoes, and corn. Drizzle with olive oil and melted butter, mixing until coated.

Sprinkle in Old Bay seasoning, garlic powder, paprika, salt, and black pepper, tossing to ensure all ingredients are evenly coated.

Cut large sheets of heavy-duty aluminum foil. Divide the mixture among the sheets to create individual packs. Seal tightly to maintain moisture.

Place the foil packs on the preheated grill or in the oven and cook for 25-30 minutes, flipping halfway through.

Carefully remove the packs and open, garnishing with parsley if desired, before serving.