Fillet of Beef Wellington

Duxelles 1 or 2 shallots, finely chopped, or 1 small onion, finely chopped 1/2 cup butter 1 pound mushrooms, finely chopped Salt Prepare the pastry. If it is rough puff paste, make 2 pounds; if brioche, make 1 recipe. Chill the dough till needed. Rub the fillet well with butter and pepper. Roast on a rack in a 400 to 450 degree oven till it registers 120 degrees, it must be very, very rare. Flame with the cognac. Remove to a rack and salt to taste. Allow it to cool completely before making the roll. If you do not, the pastry will melt in spots, causing it to be flabby and break when you cut into it. If both pastry and meat are cool, the final baking will brown the paastry and heat the meat without overcooking it, which so often happens. While the fillet is cooking, prepare the duxelles. Cook the shallots or onion in 6 tablespoons butter over low heat until translucent. Add the finely chopped mushrooms and the additional 2 tablespoons butter. Cook very slowly to dehydrate the mushrooms completely. They should turn quite dark. Stir occasionally. They will take about 1 hour or slightly longer to cook down. Cool after cooking. Measure the circumference of the fillet, and roll out the pastry to a size that will envelop it completely, with overlap at the ends and at the bottom. Reserve the trimmed-off pastry for decorations. Spread the fillet with a thin coating of foie gras or mousse of foie gras (these can be purchased in small oval tins in many good food shops and many of the better supermarkets). Then spread the pastry with cold duxelles. Place the fillet in the center of the pastry. Bring the edges of the pastry together, moisten with white of egg, and secure. When sealed, the roll should look rather smart and tailored. Roll onto a piece of sulfurized paper or foil, and transfer to a baking sheet or shallow pan. Cut small leaves and rosettes from pastry trimmings and fasten them to the roll with the egg white. Brush the pastry with the egg yolk and cream mixture. Bake in a preheated 425 degree oven 10 minutes. Reduce the heat to 375 degrees and bake another 20 minutes or until the crust looks cooked through and golden brown. Remove from the oven and allow to stand 10 to 15 minutes before sliding onto a platter. Garnish with watercress or parsley, and send to the table with a bowl of brown sauce or Bordelaise sauce. To carve through both pastry and meat it is best to use a serrated slicing knife. Each slice should be 3/4 of an inch thick. Tiny Parisienne potatoes and a puree of green beans are pleasant accompaniments. And with this, one should drink a great Burgandy.