Toss rutabaga with olive oil, salt, and pepper. Roast at 400°F for 30 to 35 minutes, stirring once, until tender and caramelized.
Bake prosciutto slices flat on a separate tray at 400°F for 8 to 10 minutes until crisp. Let cool.
Whisk olive oil, balsamic vinegar, Dijon mustard, honey, salt, and pepper for the dressing.
Divide farro or quinoa, arugula, and roasted rutabaga among bowls.
Break prosciutto into shards and scatter over bowls with goat cheese and walnuts.
Drizzle with dressing just before eating, or pack separately if prepping ahead.