Step 1: Prepare Your Lasagna Noodles: Cook the lasagna noodles according to package directions until al dente, or if using no-boil noodles, prepare them as instructed. Drain, rinse with cold water to prevent sticking, and lay them flat on parchment paper or a clean surface. Set aside.
Step 2: Cook the Garlic Butter Shrimp Scampi: In a large skillet, melt the butter and olive oil over medium heat. Add the minced garlic and crushed red pepper flakes (if using) and sauté for about 1 minute until fragrant. Be careful not to burn the garlic. Add the shrimp to the skillet and sauté for 2-3 minutes, just until they turn pink and are barely cooked through. Stir in the lemon juice and dry white wine (or seafood stock), and cook for another 2 minutes, allowing the liquid to reduce slightly. Remove the shrimp from the skillet and set aside in a bowl, leaving the pan juices in the skillet.
Step 3: Make the Creamy White Sauce: In the same skillet with the pan juices, sprinkle in the all-purpose flour. Whisk continuously for 1 minute to create a roux. Gradually pour in the whole milk and heavy cream, whisking constantly to prevent lumps. Continue to whisk until the sauce is smooth and begins to thicken. Season with salt, pepper, and the zest of 1 lemon. Let the sauce simmer gently for 5 minutes, continuing to whisk occasionally, until it reaches your desired thickness. Stir in the 1/2 cup of grated Parmesan cheese until melted and smooth. Remove from heat.
Step 4: Assemble the Lasagna: Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish. Spread about 1/2 cup of the creamy white sauce evenly over the bottom of the dish. Arrange a layer of lasagna noodles over the sauce, trimming if necessary to fit. Spoon one-third of the remaining white sauce over the noodles, then scatter one-third of the cooked shrimp evenly. Top with one-third of the shredded mozzarella cheese. Repeat these layers two more times, ending with a final layer of noodles, the remaining sauce, and the rest of the mozzarella and a sprinkle of extra Parmesan.
Step 5: Bake to Golden Perfection: Cover the baking dish tightly with aluminum foil. Bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the top is golden brown and bubbly. If you want a deeper golden crust, you can briefly place it under the broiler for 1-2 minutes, watching carefully to prevent burning.
Step 6: Rest and Serve: Once baked, remove the lasagna from the oven and let it rest for at least 10-15 minutes before slicing and serving. This allows the layers to set and makes for cleaner slices. Garnish with fresh chopped parsley and extra lemon zest, if desired. Serve hot and enjoy!