Preheat the oven to 375 degrees. Prepare a large, rimmed baking sheet with aluminum foil.
Cut the Brussels Sprouts in half and place them onto the baking sheet. Drizzle with olive oil. Season with salt and pepper. Toss to evenly coat the Brussels sprouts in the olive oil. Spread into a single layer. Bake for 25 to 30 minutes.
Meanwhile, pour the sugar and balsamic vinegar into a small saucepan. Bring to a boil over medium-high heat, stirring often. Reduce the heat to medium and continue cooking until the sauce has thickened enough that it coats the spoon. The sauce will continue thicken as it cools.
When the Brussels sprouts are done, pour the sauce over and toss to coat. Top with the dried cranberries. Serve immediately.