Preheat your grill to medium-high heat (about 375°F to 400°F) or preheat your oven to 400°F. This ensures that the shrimp cook evenly and quickly.

In a large mixing bowl, combine the peeled and deveined shrimp with olive oil, Cajun seasoning, garlic powder, paprika, salt, and black pepper. Toss until the shrimp are evenly coated. This step infuses the shrimp with flavor.

Add the diced bell pepper, sliced zucchini, corn, and sliced red onion to the bowl. Toss everything together until the vegetables are coated with the seasoning as well.

Cut four large pieces of aluminum foil, about 12x18 inches each. This will create enough space for the shrimp and vegetables without overcrowding.

Place an equal amount of the shrimp and vegetable mixture in the center of each piece of foil. This ensures even cooking and flavor distribution.

Fold the sides of the foil over the shrimp and vegetables, then fold the ends to create a sealed packet. Make sure the packets are tightly sealed to trap steam inside.

Place the foil packets on the preheated grill or in the oven. Cook for 15-20 minutes, or until the shrimp are pink and opaque, and the vegetables are tender. The steam inside the packets will help cook everything evenly.

Carefully remove the packets from the grill or oven using tongs, as they will be hot. Let them sit for a couple of minutes before opening to allow the steam to escape safely.

Open the foil packets carefully, as steam will escape. Transfer the contents to plates or serve directly in the foil for a rustic presentation.

Garnish with chopped fresh parsley and serve with lemon wedges on the side for an extra burst of flavor.