Preheat oven to 375°F (190°C). Toss Brussels sprouts with oil, salt and pepper and place on a rimmed baking sheet. Roast on middle rack of oven, stirring occasionally, 25 min. Add almonds and roast another 5 min. or until sprouts are tender-crisp, outer leaves are golden and almonds are toasted.
Transfer to a serving dish. Stir in lemon zest and juice and parsley. Drizzle with balsamic vinegar and serve.