Preheat your oven to 400°F and line a large baking sheet with parchment paper.
In a large bowl, toss the halved Brussels sprouts with olive oil, garlic powder, salt, and pepper until evenly coated.
Spread the Brussels sprouts in a single layer on the baking sheet, cut side down for maximum crispiness.
Roast for 20-25 minutes, shaking the pan halfway through, until they're golden brown and crispy on the edges.
Drizzle with balsamic vinegar if desired, and serve immediately while they're hot and crispy!