Preheat oven to 375°F. Place Brussels sprouts, apples and onion in a large bowl. Add oil, garlic powder, salt and pepper; toss to coat well.
Spread in single layer on foil-lined 15x10x1-inch baking pan that has been coated with olive oil cooking spray.
Roast 30 to 35 minutes or until Brussels sprouts are browned and tender.
Meanwhile, mix balsamic vinegar with honey in a small bowl. Drizzle over roasted Brussels sprouts, apples and onions when done. Toss to coat well and serve immediately.