Preheat the oven to 425 degrees F.
Spray a very large rimmed baking sheet with cooking spray.
Spread shrimp evenly on the baking sheet.
In a small bowl, whisk together melted butter, garlic, and Parmesan cheese.
Pour butter mixture over the shrimp and toss to coat.
Bake, uncovered, for 7-10 minutes (or just until shrimp turn pink). If you are using smaller shrimp, they will probably cook faster, so keep your eye on them!