1. Preheat oven to 425 degrees Fahrenheit (220 degrees Celsius). Spray a baking sheet with cooking spray and set aside.
2. Slice Brussels sprouts lengthwise. In a large bowl, toss brussels sprouts with one and a half tablespoons olive oil, kosher salt, and black pepper to coat thoroughly.
3. Transfer the Brussels sprouts to the baking sheet and roast until tender and caramelized, about 30–40 minutes, shaking the pan every five to seven minutes for even browning.
4. Transfer brussels sprouts to a mixing bowl. Add remaining half tablespoon olive oil, balsamic vinegar, and honey and toss to coat evenly. Taste and season with extra kosher salt if necessary.