Preheat oven to 220°C (425°F) and line a baking sheet with parchment paper.
Toss halved Brussels sprouts with olive oil, salt, and pepper, then arrange cut side down.
Roast 25 to 30 minutes, flipping once, until golden and tender.
Warm honey, toasted walnuts, Dijon mustard, vinegar, and chili flakes for 2 to 3 minutes.
Thread roasted sprouts onto soaked skewers and place on a platter.
Drizzle warm glaze over skewers, garnish with herbs, and serve warm.