For Crust: Blend flour and salt in processor. Cut in butter using on/off turns until mixture resembles coarse meal. Add enough water to blend dough. Gather dough into ball; flatten into disk. Wrap in plastic; chill 45 minutes.

Roll out dough on floured surface to 12-inch round. Transfer to 9-inch-diameter tart pan with removable bottom. Trim edges, leaving 1/2-inch overhang. Fold overhang in to form double-thick sides. Press tart edges to raise dough 1/8 inch above pan. Chill 30 minutes.

For Filling: Bring 1 cup water to boil in saucepan. Add porcini; remove from heat and let stand 30 inutes. Spoon porcini from liquid; reserve liquid. Coarsely chop procini.

Melt butter in heavy large skillet over high heat. Add procini and crimini mushrooms. Season with salt; saute until deep golden, about 10 minutes. Add shallots; saute 2 minutes. Add Cognac and reserved porcini liquid, leaving any sand behind in sauce pan. Boil until almost all liquid is absorbed, about 3 minutes. Mix in 1 tablespoon herbs. Cool.

Preheat oven to 375F. Line crust with foil. Fill with dried beans. Bake 15 minutes. Remove foil and beans; bake until golden, about 15 minutes. Maintain oven temperature.

Sprinkle 1/3 cup cheese in crust. Cover with mushrooms. Whisk cream, yolks, egg and 1 tablespoon herbs in bowl. Pour custard over mushrooms. Top with remaining cheese. Bake until filling is set and top is golden, about 30 minutes. Cool on rack 15 minutes.

From the Perigord region of France. Bon Appetit/May 94 Typed by Didi Pahl