Step 1: Cook the Pasta : Bring a large pot of salted water to a boil. Cook pasta until al dente according to package instructions. Drain and set aside.
Step 2: Prepare the Cheese Sauce : In a medium saucepan, melt 2 tablespoons butter over medium heat. Stir in flour to form a roux and cook 1–2 minutes. Gradually whisk in milk and cream until smooth. Add Dijon mustard, smoked paprika, salt, and pepper. Reduce heat to low and stir in cheddar, Gruyère, and Parmesan until melted and smooth.
Step 3: Combine Pasta and Lobster : Preheat oven to 375°F (190°C). In a large mixing bowl or directly in the baking dish, combine cooked pasta, lobster meat, and cheese sauce. Toss gently to coat pasta and lobster evenly.
Step 4: Prepare the Crispy Topping : In a small bowl, mix panko breadcrumbs, melted butter, Parmesan, and garlic powder (if using). Sprinkle the mixture evenly over the pasta and cheese sauce.
Step 5: Bake : Transfer the mixture to a greased 9×13-inch baking dish if not already in one. Bake for 20–25 minutes, until the top is golden brown and crispy. Optional: broil for 1–2 minutes at the end for extra crispiness.
Step 6: Serve : Let the baked lobster mac and cheese rest for 5 minutes before serving. Garnish with chopped parsley for color. Serve hot, optionally with a simple green salad or roasted vegetables.