In a medium sized saucepan, bring broth to a boil. Add farro and reduce heat to medium. Cook for 15-20 minutes, until farro is tender. Drain but reserve cooking liquid.
Meanwhile, heat butter and olive oil over medium heat in large skillet. Add scallions and cook for 1 minute, until fragrant. Stir in asparagus, peas, and salt. Cook for about 5 minutes, until vegetables soften.
Add in vinegar and cook for 30 seconds. Stir in drained farro and cook for about 3 minutes, then toss in Parmesan cheese. Add ½ cup reserved cooking liquid from the farro, and stir until a nice, creamy sauce forms. Add additional liquid if needed. Stir in mint and adjust salt to taste.
Divide farro among 4 bowls. Add a tablespoon of ricotta to each one, a few slices of radish, and some freshly ground black pepper.