In a large skillet or an extra-large wok, heat one tablespoon olive oil over medium-high heat. Add the Brussels sprouts and the red onion. Cook until crisp-tender, about 4 minutes. Add prosciutto, chopped walnuts and garlic and continue to cook for 2 minutes.
Add farro and the remaining one tablespoon of olive oil. Cook until heated through, about 3-4 more minutes.
To serve, drizzle mixture with balsamic and sprinkle with Parmesan cheese, chopped basil and cracked pepper.