01 - Set oven to 425°F and line a baking sheet with parchment paper.
02 - In a large bowl, toss the halved Brussels sprouts with olive oil, sea salt, black pepper, and garlic powder if using, ensuring even coating.
03 - Spread Brussels sprouts cut side down in a single layer on the prepared baking sheet.
04 - Place the baking sheet in the oven and roast for 20 to 25 minutes, flipping once halfway through, until sprouts are crisp and golden on the edges.
05 - Remove from oven, drizzle with balsamic vinegar if desired, toss gently, and serve immediately.