Thoroughly wash your hands and clean/sanitize all cooking surfaces.
Preheat oven to 400 degrees F.
In a large pot of boiling salted water, slightly cook potatoes until just tender (~10min). Stir in corn during the last 5 minutes; drain well.
In a small bowl, combine butter, lemon juice, oil, garlic and Old Bay Seasoning.
Place potatoes, corn, sausage and shrimp in a single layer on a sheet pan. Stir in butter mixture and coat all components. Add a little more Old Bay Seasoning to endure everything is seasoned.
Place in the oven and cook for 13-15 minutes, or until shrimp are opaque.
Garnish with parsley and serve immediately with lemon wedges on the side.