Yield: 4 to 6 servings.
1 cup pearl barley
1 large celery root, peeled and cut into ½-inch cubes (about 3 cups)
½ cup plus 1 tablespoon extra virgin olive oil
2 tablespoons plus 1 teaspoon salt, more as needed
Black pepper, to taste
1 pound mixed mushrooms, like cremini, oyster and hedgehog, cut into bite-size pieces
1 tablespoon cider vinegar, more as needed
3 scallions, finely chopped
1 tablespoon chopped celery leaves
⅓ cup celery stalk, finely diced
¾ cup parsley leaves.
Preheat oven to 350 degrees. Spread the barley grains on a rimmed baking sheet and toast until fragrant and golden, 20 minutes.
Increase oven temperature to 400 degrees. On a rimmed baking sheet, toss the celery root with 2 tablespoons oil, .25 teaspoon salt and pepper. On a separate baking sheet, toss the mushrooms with .25 cup oil, .5 teaspoon salt and pepper. Roast both, tossing occasionally, until golden and tender, 15 to 20 minutes for the mushrooms, and 30 to 40 minutes for the celery root. Transfer to a large bowl.
Meanwhile, in a large pot, bring 10 cups water and 2 tablespoons salt to a boil. Add the barley and simmer until tender, 45 to 50 minutes; drain. Add to the mushrooms and celery root.
In a small bowl, whisk the vinegar, scallions, celery leaves, .25 teaspoon salt and pepper. Whisk in 3 tablespoons oil. Toss the vinaigrette and diced celery stalk into the salad. Coarsely chop .25 cup parsley leaves and add to the salad. Toss in the remaining whole leaves, tearing larger leaves into smaller pieces. Taste and adjust seasonings, if necessary. Serve warm or at room temperature.