Pre-heat oven to 425 degrees F. Using a large baking sheet, season brussels sprouts, bacon pieces and garlic with salt and pepper. Drizzle with oil and toss until combined. Bake until brussels sprouts are tender and charred, 25-30 minutes.
In the meantime, make the balsamic glaze. In a small saucepan, combine balsamic vinegar, honey and rosemary. Simmer until reduced by half, stirring occasionally, 12-15 minutes. The glaze should coat the back of a spoon. Let cool.
Drizzle over the roasted brussels sprouts and serve.