01 - Preheat oven to 400°F. Grease a 2-quart baking dish with butter or cooking spray.
02 - Bring a large pot of salted water to boil. Cook macaroni until al dente according to package directions. Drain well and set aside.
03 - In a large saucepan over medium heat, melt 3 tbsp butter. Whisk in flour and cook for 1 minute, stirring constantly to form a smooth paste.
04 - Gradually whisk in the whole milk, continuing to stir to prevent lumps. Simmer for 4-5 minutes until sauce thickens enough to coat the back of a spoon.
05 - Remove from heat. Stir in cheddar, Gruyère, and Parmesan until completely melted and smooth. Add Dijon mustard, smoked paprika, salt, and pepper.
06 - Gently fold the cooked macaroni and chopped lobster meat into the cheese sauce until evenly distributed.
07 - Pour the lobster mac and cheese mixture into the prepared baking dish, spreading evenly.
08 - In a small bowl, combine panko breadcrumbs with melted butter and chopped parsley. Mix until breadcrumbs are evenly coated.
09 - Sprinkle the breadcrumb mixture evenly over the top of the mac and cheese.
10 - Bake for 20-25 minutes until the topping is golden brown and the cheese sauce is bubbling around the edges. Let rest for 5 minutes before serving.