Preheat the Oven: Set your oven to 400°F (200°C) and line a large baking sheet with foil or parchment paper for easy cleanup.
Parboil the Potatoes: Bring a large pot of salted water to a boil. Add the baby potatoes and cook for 10 minutes, just until slightly tender but not fully cooked. Drain and set aside.
Parboil the Corn: In the same pot of boiling water, add the corn pieces and cook for 4 minutes. Drain and let cool slightly.
Assemble on the Sheet Pan: Add the parboiled potatoes, sausage slices, and corn to your baking sheet. Drizzle with a little olive oil, then season generously with Cajun seasoning, garlic powder, onion powder, parsley, paprika, salt, and pepper. Toss everything together until evenly coated.
Roast the Base: Place the baking sheet in the oven and roast for 12 minutes. This helps the sausage brown and the potatoes start to crisp up.
Add Shrimp and Butter: Remove the sheet pan from the oven and add the raw shrimp on top. Scatter the cut-up butter pieces and minced garlic evenly across the pan. Toss gently to coat everything in the melted butter as it cooks.
Finish Roasting: Return the pan to the oven and cook for another 7 minutes or until the shrimp are pink, opaque, and fully cooked. Keep an eye on them — shrimp cook quickly!
Serve Hot: Once done, give the mixture a final toss to coat everything in the buttery garlic sauce. Serve immediately straight from the pan for a rustic presentation, or transfer to a large serving platter.
