Break dried porcini mushrooms into smaller pieces.

Process in food processor, high-speed blender or spice grinder for 2-3 minutes until very finely ground into powder.

Pour powder through a fine mesh sieve to remove any remaining chunks.

Reserve extracted dried mushroom pieces to use in soups and stocks.

Transfer filtered porcin powder to an airtight container. Store in a cool, dark place for up to 1 year.