Burdock is a plant with many uses. Although in the United States it is treated more as a weed, in Japan it is cultivated as a vegetable. Burdock is native to Europe and is a member of the daisy family. Growing to a height of three to four feet, it blooms with purple flowers. It is the roots of the plant, however, that are utilized for medicinal purposes and for culinary uses. Burdock roots must be harvested during their first year or they become tough. Creating flour from the root of the burdock is a lengthy process. This recipe will yield 14 ounces of burdock flour.
Preheat the oven to 150 degrees F, or the lowest temperature setting on your oven.
Scrub the burdock roots under running water, very much in the same manner that you scrub potatoes.
Chop the root into large chunks and drop them into boiling water. Allow to boil gently for 45 minutes.
Drain the water and allow the roots to cool until they can be handled.
Grind the root pieces in the food processor until they are completely smashed.
Spread the root pulp in a thin layer on a baking sheet and place the sheet in the oven, leaving the oven door ajar. Allow it to remain in the oven for 20 hours.
Mix the pulp, crumbling any large pieces, spread over the baking sheet again and place back in the oven for another 24 hours.
Grind the flour in a mill or other grinder until it is a fine powder.