-
1
Preheat the oven to 375 degrees F and butter a 3-quart baking dish.
-
2
Set aside.
-
3
Melt 4 tablespoons of the butter in a medium saucepan over medium-low heat.
-
4
Add the onion and cook until it softens, about 5 minutes.
-
5
Add the garlic and cook until fragrant, about 1 minute.
-
6
Add the flour, stirring with a wooden spoon, and cook 1 minute.
-
7
Pour in the milk, using a whisk to make sure it blends with the onion-flour mixture.
-
8
Bring to a boil, still over medium-low heat, whisking often.
-
9
Simmer until the sauce is smooth and slightly thickened, about 3 minutes.
-
10
Remove the sauce from the heat and add both cheeses, whisking until melted.
-
11
Add the Dijon, chives, cayenne, and 12 teaspoon each of salt and black pepper.
-
12
Transfer the mixture to a large mixing bowl and stir in the cooked pasta and lobster.
-
13
Pour into the prepared baking dish.
-
14
In a small mixing bowl, combine the panko with the remaining 2 tablespoons of butter, melted.
-
15
Season with the remaining 14 teaspoon salt and black pepper.
-
16
Sprinkle over the casserole and bake until the mac and cheese is bubbling and the crust is crisp and golden brown, about 30 minutes.
-
17
Let the casserole rest on a cooling rack for 5 minutes before serving.
