Look for beets with bright, vibrant greens without too many holes or brown bits on the leaves. Hulled barley contains more fiber and nutrients than does pearled barley. It’s also more difficult to find and takes longer to cook. Either is just dandy here.
Put the barley in a medium pot and add enough water to cover by about 1 in/2.5 cm.Bring to a boil, cover, and lower the heat to maintain a steady simmer.Cook until the barley is tender to the bite, about 30 minutes for pearled barley and 45 minutes for hulled.Set aside.(You can pour off any truly excess water, but there is no need to drain it—it’s going into a soup, so a bit of water won’t hurt anything.)
Meanwhile, preheat the oven to 350°F/180°C.Cut the beets from their greens.Scrub the beets clean, wrap them in a large sheet of foil, and place on a baking sheet.Bake until they’re tender when pierced with a fork, about 45 minutes.
Let the beets sit until cool enough to handle.Peel them (their skins should slip off easily after being roasted) and grate them on the large-hole side of a box grater.Set aside.(I like the ease of peeling and grating roasted beets, but feel free to peel and grate raw beets— they will cook quickly enough in the soup.)
Rinse the beet greens clean, as they often have a fair amount of grit on them. Separate the beet green stems from the beet green leaves.Chop the stems, then chop the leaves; keep the stems and leaves separate.
In a large pot over medium-high heat, melt the butter.Add the onion, beet stems, and 1/2 tsp salt.Cook, stirring occasionally, until the vegetables are softened, about 3 minutes.Stir in the grated beets, then add the chicken broth.Bring to a boil, lower the heat to maintain a steady simmer, and cook until the vegetables are tender, about 15 minutes.
Add the beet greens and cooked barley, and cook until the beet greens are tender and the flavors are blended, about 10 minutes.
Stir in the lemon juice. Adjust the seasoning with more salt and/or lemon juice.
Serve hot, with a dollop of yogurt and a sprinkle of caraway seeds and dill, if you like. This soup keeps nicely up to 2 days in the fridge or 6 months in the freezer.
Reprinted with permission from Greens + Grains: Recipes for Deliciously Healthful Meals by Molly Watson (Chronicle Books, © 2014).