1. Start by seasoning 1 lb. of peeled and deveined shrimp with a sprinkle of salt, black pepper, and Italian seasoning. Toss gently to coat evenly.
2. Heat 3 tablespoons of olive oil or butter in a skillet over medium heat. Sauté 1 finely chopped small onion until translucent, about 3-4 minutes.
3. Add 5 minced garlic cloves to the skillet and sauté for an additional minute until fragrant.
4. Add the seasoned shrimp to the skillet and cook for about 2-3 minutes per side, until they turn pink and are just cooked through. Be careful not to overcook.
5. Lower the heat under the skillet and stir in 1/2 cup of cream or sour cream to create a smooth, creamy sauce. Allow the flavors to blend.
6. Preheat your oven to 375°F (190°C). Transfer the shrimp and creamy sauce to a greased baking dish.
7. Evenly spread 1 cup of grated cheese (Manchego, mozzarella, or Parmesan) over the shrimp mixture to create the gratin topping.
8. Place the baking dish in the preheated oven and bake for 12-15 minutes, or until the cheese has melted and is golden and bubbly.
9. Remove the dish from the oven and let it cool slightly before serving.
10. Garnish with freshly chopped parsley or chives for a flavorful and fresh finishing touch.
11. Serve the Garlic Shrimp Gratin immediately, pairing it with a side of fresh salad, rustic bread, or complementary pasta. Enjoy!