Heat oven to 400ºF (200ºC). Toss the Brussels sprouts in the olive oil and balsamic and spread in an even single layer on a baking sheet. Season with salt and pepper.
Roast until the Brussels sprouts are golden brown and slightly charred, about 20 to 25 minutes.
Add the bacon to a medium sauté pan. Turn the heat up to medium, and sauté, stirring occasionally until the bacon is crispy, about 5 minutes. Using a slotted spoon remove the bacon from the pan to a paper towel-lined plate to drain.
Top the roasted Brussels sprouts with the crispy bacon pieces and serve hot.