How to Make It
In a large saucepan of boiling water, cook the barley until tender, about 30 minutes. Drain.
Meanwhile, in a large skillet, heat the olive oil. Add the mushrooms and shallots and cook over moderate heat, stirring, until golden and tender, 5 to 7 minutes. Stir in the lemon juice and barley and season with salt and pepper. Transfer to a serving dish and garnish with scallions.