Remove the heads and claws from the scampi and reserve. Wash the tails. In a mixing bowl crush the scampi heads and claws with a rolling pin. Melt 2 tablespoons of the butter in an ovenproof casserole or Dutch oven and cook the shells gently for 10 minutes. Add all of the vegetables, the bouquet garni, the clove, and 8 cups of water. Bring to a boil and simmer for 1 1/2 hours. Strain through a fine-mesh sieve, pressing hard to release all of the juices. Return the sauce to the pan and reduce further if necessary. Set aside. In a frying pan melt the remaining butter and cook the mushrooms until softened, about 5 minutes. Add the crÅme fraöche and boil until thickened. Keep warm. Remove the shells from the scampi. Melt the remaining butter in a non-stick frying pan and cook the scampi for 1 minute per side, turning once. Remove the scampi from the frying pan and keep warm. Add about 1 cup of the stock to the frying pan and bring to a boil, scraping the bottom of the frying pan with a wooden spoon to dislodge any shellfish particles. Spoon the creamed mushrooms onto a serving platter and arrange the scampi on top. Season the sauce and pour it over the mushrooms and scampi. Serve immediately.
