1. To prepare the farro, soak it in water for 2 hours. Cook it in boiling salted water for 15 minutes; drain.
2. In a large saucepan, heat 3 tablespoons of extra virgin olive oil over medium heat. Add the onions and cook until they are transparent. Add the farro and mix well. Add the glass of wine and mix, until the wine is completely evaporated. Add enough broth to cover the farro and cook until the liquid is reduced by half, stirring constantly. Add more broth to cover, and cook in this way, until the farro is ready.
3. Add all the herbs and parmesan. Mix well. Gently add the tomatoes in pieces and the grated lemon zest.
4. Serve in small portions. Add a splash of extra virgin olive oil.
Variation: if served cold, replace the grated parmesan with mozzarella cubes.