Relatively difficult to make, but perfect for a festive meal, this gratin is one of the great classics of alpine cuisine.
Difficulty:[usr 3]
Wash the crayfish under running cold water, then castrate them by removing the very last part of the abdomen (tail) and the intestines (small black twist). Peel the carrots and shallots. Chop them as finely as possible. Scald the tomato, peel it and cut it in half to remove the seeds. Cut it into small dice.
Heat 20 g of butter in a saucepan, add the shallots and carrots, mix and sauté for 10 minutes, stirring. Then add the crayfish and turn up the heat. Sauté them briskly for 5 minutes, holding the lid on the pan. Pour the cognac after heating it in a ladle and flambé. Mix, then pour in the white wine and add the crushed tomato, 1 sprig of thyme and 1 bay leaf. Add salt and pepper. Cover and cook gently for 5 minutes.
Remove the crayfish with a slotted spoon and separate the heads from the tails. Set these aside. Mash the heads with a wooden pestle and return them to the pan. Cook for 5 minutes, then add the fresh cream and bring to the boil. Pass the contents of the pan through a sieve or a colander lined with cheesecloth to collect all the sauce.
Pour this sauce into a clean saucepan. Mix the rest of the butter with a tablespoon of flour and bind the sauce with this butter handled incorporated by small parcels. Whisk this sauce until smooth and keep warm. Also, shell the crayfish tails. Coat the bottom of a gratin dish (or individual cassolettes) with sauce, place the crayfish tails in it, then cover them with the rest of the sauce. Glaze under the broiler for about 2 minutes and serve piping hot in the baking dish.
Do not hesitate to crush the heads of the crayfish well to obtain the maximum of juice and therefore a very tasty sauce.
Note from chef Hubert:for my part, we can do without "handled" butter, in other words no flour.
Source:Les Cuisines Régionales de France. Savoie-Dauphiné. Editions du Fanal.
