If you are using frozen brussel sprouts, thaw them on a couple of paper towels, making sure to press hard to remove any excess liquid to make them as dry as possible once they are thawed. Slice them in half then toss them with olive oil and sea salt and freshly cracked pepper, to taste. Place them onto the prepared baking sheet. Sprinkle them with the diced pancetta. Place into the oven and roast for 15 minutes. Flip them over then continue roasting for 5-10 more minutes, or until caramelized. Remove from the oven and drizzle with balsamic vinegar, to taste. Serve immediately. Enjoy.