Heat one tablespoon olive oil over medium heat in a medium pot. Add onion and cook until clear, about eight minutes. Add garlic and cook until fragrant, about one minute. Stir in farro and toast about four minutes, stirring constantly. Add wine and cook until absorbed, about two minutes. Pour in broth and tamari, add pepper, bring to a rolling boil. Cover and reduce heat to medium. Cook 25 minutes. Uncover and cook, stirring often, until remaining liquid is absorbed, about five to ten minutes.

Meanwhile, heat remaining tablespoon of olive oil in a skillet over medium heat. Add mushrooms and season with salt, cook until tender and just brown on the edges, about five to seven minutes. Stir in walnuts and toast for a minute. Remove from heat. When farro is ready, stir in mushrooms, parsley, and chives.