Step 1: Prepare the Shrimp
Preheat your oven to 400°F (200°C). Toss the peeled and deveined shrimp with olive oil, salt, and pepper. Arrange the shrimp in a single layer in a greased baking dish and set aside.

Step 2: Make the Garlic Sauce
In a medium saucepan, melt the butter over medium heat. Add the minced garlic and sauté for 1–2 minutes, or until fragrant.
Whisk in the flour and cook for another minute to form a roux. Gradually add the heavy cream, whisking continuously to avoid lumps. Cook for 2–3 minutes until the sauce thickens slightly.
Stir in the Parmesan cheese, paprika, red pepper flakes (if using), and chopped parsley. Remove the sauce from the heat.

Step 3: Assemble the Gratin
Pour the garlic sauce evenly over the shrimp in the baking dish, ensuring all shrimp are covered.

Step 4: Prepare the Breadcrumb Topping
In a small bowl, combine the panko breadcrumbs, melted butter, and Parmesan cheese. Mix well until the breadcrumbs are evenly coated. Sprinkle the breadcrumb mixture over the shrimp and sauce.

Step 5: Bake the Gratin
Place the baking dish in the preheated oven and bake for 15–20 minutes, or until the shrimp are pink and opaque and the topping is golden brown and crispy. For extra crispiness, broil the gratin for the last 1–2 minutes.

Step 6: Garnish and Serve
Remove the gratin from the oven and let it rest for 5 minutes. Garnish with additional parsley before serving. Enjoy with crusty bread, rice, or a fresh green salad.