1. Heat oil in a large saucepan over medium heat. Add onion and cook, stirring often, until softened.
2. Add pearl barley and wild rice; stir for a few seconds. Add broth and bring to a simmer.
3. Reduce heat to low, cover, and simmer until the wild rice and barley are tender and most of the liquid has been absorbed, 45 to 50 minutes.
4. Toast pine nuts in a small, dry skillet over medium-low heat, stirring constantly, until light golden and fragrant, 2 to 3 minutes. Transfer to a small bowl to cool.
5. Add pomegranate seeds, lemon zest, parsley, and toasted pine nuts to the pilaf; fluff with a fork. Serve hot.