Autumnal colors and flavor, slightly Japanese, this is a simple dish for those who enjoy mild, low-key, monochromatic dishes. It is subtle, with no bright contrasts in texture or taste; no sharp edges.
Peel part of burdock, immediately slice in thin diagonals, and drop into water-baking-soda mixture in nonaluminum pot. Continue until all is peeled. Bring to a full, rolling boil; drain and rinse.
Combine burdock in small, heavy pot with sliced mushrooms and salted water; simmer, covered, until tender—about 10 minutes.