• Make sure your mushrooms are cleaned of dirt and that the root is cut off.
• Slice them into uniform thin slices. Whether they are 3 mm or 8 mm thick doesn't matter much, just that they are uniform. I used a mandoline, but you can easily use a knife. Mine were about 4 mm thick.

Drying (dehydrating) in the oven

• The thinner the slices, the better.
• Place the slices in an even layer on a baking paper-lined baking sheet.
• Cook them at 50 degrees Celsius (122 degrees Fahrenheit) fan-forced for about 8-10 hours, depending on their thickness.

Drying (dehydrating) in a dehydrator

• Here, the slices can be a bit thicker than in the oven, but the thinner they are, the faster the process.
• Set your dehydrator to 55 degrees Celsius (131 degrees Fahrenheit) and set it to 9 hours.
• Place the mushroom slices in the trays, ensuring they do not touch each other.
• Check on the mushrooms after 8 hours; they might be done by then or may need up to 10 hours - it depends on their thickness and the quality of your dehydrator.

Storage

• They should be completely dry and snap/crisp when broken.
• Take them out of the oven and let them cool, preferably on a wire rack.
• Place them in a jar or another container with a lid.
• Store them in a dark and cool place.

Dehydrating mushrooms

• Place the dried mushrooms in a bowl with cold water. Let them sit for about 30 minutes and they are now ready to use. The water can be used in your stew/risotto or similar.

Mushroom stock

• Bring water and dehydrated mushrooms to a boil. Optionally, add root vegetables or other vegetables.
• Let them simmer for 10 minutes, then turn off the heat and cover the pot.
• Let it steep; the longer it sits, the more flavor it will have.