This section is from the book "Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc.", by George Francis Atkinson. Also available from Amazon: Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc..
These mushrooms, having very thin flesh and deep gills, must be quickly cooked to be good. Remove the stem, take the mushrooms in your hand, gill side down, and with a soft rag wash carefully the top, removing all the little brown scales. Put them into a baking pan, or on a broiler. Melt a little butter, allow it to settle, take the clear, oily part from the top and baste lightly the mushrooms, gill sides up; dust with salt and pepper. Place the serving dish to heat. Put the mushrooms over a quick fire, skin side down, for just a moment; then turn and boil an instant on the gill side, and serve at once on the heated plate.
In this way Lepiota procera is most delicious of all mushrooms; but if cooked in moist heat, it becomes soft, but tough and unpalatable; if baked too long, it becomes dry and leathery. It must be cooked quickly and eaten at once. All the edible forms may be cooked after this recipe.
These are perhaps the best of all mushrooms for drying. In this condition they are easily kept, and add so much to an ordinary meat sauce.