Rinse farro, then place it in a medium stockpot and cover with cold water by 2 inches. Season water with 1 tablespoon salt and several turns of pepper and bring to a boil over high heat. Lower the heat to maintain a simmer and skim off any foam that rises to the surface, then add a few twirls of olive oil. Cook gently until the grains are truly al dente—tender but with a little chew and no trace of graininess or chalkiness at the center, 35 to 40 minutes (25 minutes if using pearled farro).
Spoon farro and some of its cooking liquid into shallow bowls. Season with a few grinds of pepper and a drizzle of olive oil. Top with plenty of grated Parmigiano.