Preheat the oven to 400 °F.

Cook the lobster tails by steaming them for 1 minute an ounce, until the meat reaches an internal temperature of 135 °F. Place the tails in an ice bath to stop the cooking. Once cool, remove the meat from the shell and roughly chop it. Set aside.

Cook the cavatappi pasta according to the package directions. Drain and set aside.

Meanwhile, in a small pot, melt 2 tablespoons of the butter over medium heat until it's bubbly and melted, about 2 minutes.

Add the flour and cook, stirring constantly, until the roux is frothy and smells nutty, about 3 to 5 minutes.

Slowly whisk in the heavy cream followed by the milk. Bring the mixture to a simmer over medium heat. Cook for 5 minutes, until the liquid is lightly thickened.

Remove the pot from the heat and add 1-1/2 cups of the cheddar cheese one handful at a time, stirring until it's melted before adding the next handful of cheese. Follow the cheddar cheese with the Gruyere and Parmesan cheeses. When all the cheese is added and incorporated, stir in the salt.

Toss the cooked pasta with the cheese sauce until it’s evenly coated.

Grease the bottom of a 9 x 13 baking pan (or any 3-quart oven-safe dish) with butter. Add the pasta and cheese sauce to the baking dish. Sprinkle the cooked, chopped lobster meat evenly over the top of the pasta. Top the dish with the remaining 1/2 cup of cheddar cheese.

Bake for 20 to 25 minutes, until golden and bubbly.

Top with chopped chives before serving.