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