A rich starter, this gratin is very popular in Lyon cuisine for festive meals, for example for New Year's Eve, preceded by oysters and followed by a truffled chicken.
Difficulty [usr 3]
Carefully wash the crayfish, drain them and castrate them if necessary (remove the small black gut under the tail):you can also (instead of this delicate operation) marinate them in milk for 2 hours, then rinse them abundantly. Cook them in court-bouillon for 10 minutes, drain them and let them cool.
Clean the mushrooms and slice them. Shell the crayfish tails and collect all the flesh possible from the shell. Heat a little butter in a sauté pan, add the crayfish tails and the recovered flesh as well as the mushrooms. Cook for a few minutes, stirring, salt and pepper. Remove from heat.
Prepare a Béchamel sauce with 50 g of butter, 50 g of flour, 30 cl of milk and 20 cl of fresh cream, salt, pepper and nutmeg. Then mix the creamy Béchamel sauce, the crayfish meat and the mushrooms, then add a tablespoon of crayfish butter.
Butter a gratin dish, pour the preparation into the dish and brown for 10 minutes in the oven. Serve immediately.
If you can, add a minced truffle in the preparation when mixing all the ingredients.
Source:Regional Cuisines of France:Le Lyonnais
