The Mycological Society of San Francisco offers a recipe for Parmesan puffballs. In addition to the recipe, the society's website provides general tips for identifying, cleaning and cooking foraged puffball mushrooms.
To make Parmesan puffballs, slice 1 pound of puffball mushrooms into 1/2-inch slices. The Mycological Society of San Francisco recommends using a knife to carefully peel away the outer coating before slicing, as this coating can cause intestinal irritation in sensitive individuals.
In a bowl large enough to dip the mushroom slices, mix 1 cup of flour with 1 teaspoon of salt. Beat 1 egg with 2 tablespoons of water in a second bowl. Add 1 cup of freshly grated Parmesan cheese to a third bowl.
Dip a puffball mushroom slice into the flour, then dip it in the egg. Finally, dredge the slice in the Parmesan cheese. Repeat this process for each slice of puffball mushroom.
Heat 4 tablespoons of butter and 2 tablespoons of oil in a skillet or saute pan. When the butter has melted, add the breaded puffball mushroom slices. Cook the slices slowly until golden brown on both sides, turning as necessary. Drain the puffball mushroom slices on paper towels and serve immediately as an appetizer.