01 - Preheat the oven to 425°F. Line a large baking sheet with parchment paper.
02 - In a large bowl, combine the halved Brussels sprouts with olive oil, sea salt, black pepper, and chili flakes if using. Toss thoroughly to coat evenly.
03 - Spread the Brussels sprouts in a single layer on the prepared baking sheet, placing them cut side down.
04 - Roast for 20 to 25 minutes, stirring once halfway through, until the edges are crispy and deeply golden.
05 - Remove the sprouts from the oven, immediately drizzle with honey and apple cider vinegar, then toss well to ensure even coating.
06 - Transfer to a serving dish and sprinkle with toasted sliced almonds if desired. Serve warm.