Escarole and Farro Soup

¾ cup farro
2 tablespoons olive oil
1 medium yellow onion, chopped
2 medium carrots, chopped
2 celery ribs, chopped
2 garlic cloves, finely chopped
6 cups chicken stock, preferably homemade, or use low-sodium canned broth
One 14½-ounce can diced tomatoes, with juice
One 12-ounce head escarole, well rinsed, hard stems removed, and coarsely chopped
Salt and freshly ground black pepper
Chopped fresh parsley, for serving
Freshly grated Parmesan, for serving

This satisfying soup is similar to minestrone and other rustic Italian soups.

The night before making the soup, put the farro in a bowl and add enough cold water to cover by 1 inch. Let stand in a cool place or refrigerate for at least 12 hours.
Drain the farro in a wire sieve. Bring a medium saucepan of lightly salted water to a boil over high heat. Add the farro and reduce the heat to medium-low. Simmer until the farro is tender, about 30 minutes. Drain the farro and set aside.
Meanwhile, heat the oil in a large pot over medium heat. Add the onion, carrots, and celery and cook, stirring occasionally, until softened, about 5 minutes. Stir in the garlic and cook until it gives off its fragrance, about 1 minute. Stir in the stock and the tomatoes with their juice. Bring to a boil over high heat. Reduce the heat to mediumlow and simmer for 45 minutes.
Add the cooked farro and escarole. Cook, stirring occasionally, until the escarole is very tender, about 15 minutes. Season with salt and pepper to taste.
Serve hot, sprinkling each serving with parsley, and with the cheese on the side.