Mushroom Barley Soup in the MIddle-European Manner

20 dried mushrooms, chopped (2 oz), or more
16 cups vegetable broth (1/2 from bouillon is fine, up to 2 cups can be water)
8T butter, divided into 4T + 4T
2 medium white onions, chopped
2 carrots, chopped
2 celery stalks (not bunches, just stalks), chopped
1 cup pearl barley
4T (level) flour

This recipe makes a double batch, as we pretty much never have just one batch.

Chop onions, celery, carrots.
Chop mushrooms into desired size, larger if they need to be pulled out.

Large pot, melt 4T butter, dump in vegetables, stir, cover. Cook 10ish minutes, stir frequently, until vegetables are soft but not browned.

While cooking, rinse barley until water becomes clear.

Dump in the broth all at once. Add barley. Add mushrooms. Bring to boil, then reduce to a simmer. Simmer for 50 minutes.

After 50 minutes, small pan, melt the remaining 4T butter, then add the flour. This is the roux. Cook over medium heat until the flour is a "delicate golden brown," but who knows WTF that is, so, a deep tan.

Dump the roux into the soup, it'll sizzle. Stir it in. Simmer for another 15-20 minutes. Check the barley is cooked, everything else will be fine.

If the soup is too thick, add water.

Serve.

Is great the next day, reheated.