- Preheat oven to 425℉.
- On a parchment-lined baking sheet, toss together Brussels sprouts, onion, and dressing and distribute in an even layer.
- Roast until tender and caramelized, about 15 minutes.
- Transfer Brussels sprouts to a serving bowl, and top with feta, cranberries, and hazelnuts. Drizzle with more dressing to taste.