Wild Mushrooms are a great delight if you are careful and only pick the right varieties. If you find a crop of parasols or perhaps some ceps, then you will want to dry some and use them throughout the coming year.
I know mushrooms aren’t technically vegetables, but forgive me this little faux pas.
To dry mushrooms in an oven, first slice the cleaned mushrooms thinly. Woody stalks (the parasol for example) can be discarded. Place the sliced mushrooms in shallow unoiled trays and place in the oven. Heat the oven to no higher than 150 degrees Fahrenheit (about 70c) and let the mushrooms dry for an hour. After an hour turn the slices and return to the tray for another hour of gentle drying.
If they still hold water, just do it all again until they are bone dry. Now you can store in sealed jars (with a little salt to absorb any atmospheric moisture).
Of course, to be really environmentally friendly, consider air drying and for something special why not have a go at cold smoking the mushrooms you collect.