Step 1

In a frying pan, heat 2 tablespoons butter and when hot add the shallots and sauté for a couple of minutes, add the lobster pieces.  Cook for about 5 minutes; add the tarragon, cook for another minute and add the sherry and the cognac.  And turn off the heat and reserve.

Step 2

In a saucepan, heat 4 ounces of butter; when hot, add the flour and mix well to create your roux.  Add ½ of the milk, and using a whisk, mix well.  When well incorporated, add the remaining milk.  When everything is nicely mixed, add the cheeses and blend well.

Step 3

Add the pasta and the lobster.  Adjust the seasoning with salt and pepper and transfer to your buttered lasagna pan. Top with the breadcrumbs and the parmesan and bake for about 25 minutes or until it is nicely golden brown.