Clean mushrooms with a kitchen towel, brushing off any dirt or grit.
Cut mushrooms into ¼” slices or pieces.
Arrange mushrooms in a single layer on dehydrator trays, ensuring there is space between pieces to allow airflow.
Dehydrate at 125F for 6-8 hours, until the mushrooms are completely dry. They should be brittle and break, not bend, when fully dry.