Preheat Oven: Preheat oven to 400 degrees F.
Prepare Potatoes: In a large bowl, toss halved potatoes with 2 Tablespoons olive oil and 2 teaspoons Old Bay seasoning. Spread them out on a large sheet pan.
Bake Potatoes: Transfer sheet pan to the oven and bake for 20 minutes.
Prepare Corn and Sausage: While potatoes are baking, toss corn pieces and sliced sausage in the same bowl with another 1 Tablespoon olive oil and 2 teaspoons Old Bay seasoning.
Add Corn and Sausage: After potatoes have baked for 20 minutes, add corn and sausage to the sheet pan. Stir everything together to combine. Return pan to the oven and bake for another 10 minutes.
Prepare Shrimp: In the same bowl, toss shrimp with remaining 1 Tablespoon of olive oil, remaining 1 teaspoon of Old Bay seasoning, and minced garlic.
Add Shrimp and Lemon: After the corn and sausage have baked for 10 minutes, add shrimp and lemon wedges to the sheet pan. Stir everything together again and spread it out evenly. Bake for another 5-7 minutes, or until the shrimp are pink and cooked through.
Serve: Remove the sheet pan from the oven. Garnish with chopped parsley, then serve.
