Add the ingredients to a blender. Place the dried shiitakes and salt into the bowl of a high-speed blender.
Blend. Blend for 30-40 seconds or until you get a very fine powder. Be aware that the mushroom powder is very fine and light, a bit like powdered sugar. So, after blending, I highly recommend waiting for a couple of minutes before opening the blender lid for the powder to settle a bit.
Transfer to a container. Finally, transfer the mushroom seasoning to a clean glass container or jar.
Use in broth, soups, marinades, or dips to add an umami flavor!
This mushroom powder can be stored for up to 12 months in an airtight container at room temperature. Do not refrigerate it, otherwise it might clump and grow mold because of the humidity.
Notes
Dry it over low heat.
Some brands of dried mushrooms may have more moisture than others. That can lead to a powder clumping together. In case, after blending, the powder is not dry enough, you can heat it in a pan (without any oil) for 5-7 minutes to make it drier. Make sure to cook it over low heat and stir very regularly so as not to burn it.
Sieve it.
For a super fine powder, I recommend passing it through a very fine sieve after blending.
Store in a dry place.
Like any spice or dried herbs, this powder should be stored in a dry place at room temperature. Do not store it in the refrigerator.