Place 4 beetson a large piece of foil and rub with 1 tablespoonoil; season with salt and pepper and closeup foil around beets.
Place on a rimmedbaking sheet and roast until tender, 30–40minutes. Unwrap beets and let cool slightly.Peel and cut into 1/2" wedges.
Meanwhile, whisk miso, vinegar,remaining 2 tablespoons oil, and 3 tablespoons water ina small bowl. Set dressing aside.
Thinly slice remaining 2 raw beets on amandoline. Arrange watercress and roastedand raw beets on a platter and drizzle withreserved dressing; top with sesame seeds.
DO AHEAD: Beets can be roasted2 days ahead. Cover separately and chill.
