Preheat the oven to 375 degrees F.
Bring a large pot of salted water to a boil. Add the macaroni and boil until the pasta is cooked, 8 to 10 minutes.
In a large bowl, mix the cooked pasta, Cheese Sauce, lobster, scallions and chives. Place in a baking pan and cover the top with the mixed cheeses. Bake until the top is browned, about 30 minutes. Remove from the oven and garnish with fresh chives.
In a medium saucepot, combine the flour and butter. Cook 5 minutes over medium heat while whisking. Add the milk and bring to a simmer, continually whisking. Cook over low heat, 10 minutes. Slowly add the cheeses and continue whisking until melted. Add the lobster stock, cognac, hot sauce, nutmeg and salt and pepper, to taste. Remove from the heat and set aside until needed.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Michael Ferraro, macbar