Step 1

Preheat the oven to 350°F.

Step 2

Fill a pot with salted water, and bring to a boil. Cook the macaroni for about 8 minutes, until al dente (cooked, but still a bit firm).

Step 3

In a saucepan, melt 2 tablespoons of butter, Add the onion, and cook until the onion is cooked through- about 5 minutes. Scrape the onions in a bowl; set aside.

Step 4

Add the milk, shallot, garlic and peppercorns to the saucepan. Simmer over low heat for 20 minutes.

Step 5

In a separate medium-large pan, melt 5 tablespoons of butter over low heat. Whisk in the flour, and stir until the flour has browned- about 5 minutes. Strain the milk through a sieve, and gradually whisk the milk into the flour mixture in the pan. Simmer over medium heat until the mixture is thick and smooth- about 10 minutes.

Step 6

Stir the cheeses into the milk mixture until the cheeses have melted. Season to taste with salt and pepper. Stir in cooked pasta, onions and the lobster meat. Scrape the mixture into a 4-quart casserole. Sprinkle with panko crumbs.

Step 7

Bake for 8 to 12 minutes, until the sauce is bubbly and the bread crumbs have browned.