This hearty vegetarian soup was inspired by a recipe in “Bottom of the Pot” by Naz Deravian, who explains that she created the dish by combining two classic Persian soups: lentil and barley. She uses dried limes common in Persian cuisine to infuse the broth with unique citrus notes. We opted for easier-to-find fresh limes and use the zest for fragrance and flavor and the juice to add tanginess. For efficiency, prep the spinach and cilantro while the barley and lentils cook. And to round out the meal, serve with warmed bread or flatbread and a dollop of plain yogurt for richness.