Pre-heat the oven to 425º Fahrenheit.
To a large mixing bowl, add the halved brussels sprouts, olive oil, salt, and pepper. Use your hands to combine until all the sprouts and outer leaves are well-coated in the olive oil.
Add the contents of the mixing bowl to a sheet pan and arrange the brussels sprouts so that they are all face-down in a single layer. This will result in more crispy brussels sprouts.
Tip: I don't suggest using parchment paper on the sheet pan, as it can slightly diminish the crispiness. Roasting right on the pan will yield best results.
Roast in the pre-heated oven for 25-35 minutes or until crispy and cooked through. Cooking time may vary due to size of the vegetable.
While roasting, add diced bacon to a large skillet on medium-low heat and cook until crispy.
Lower the heat and add the balsamic vinegar to the pan. Allow balsamic to gently simmer until thickened, about 3 minutes. Turn off the heat.
Once the brussels sprouts are done roasting, remove them from the oven. Gently pour the contents of the bacon balsamic mixture over the brussels sprouts and use a spatula to combine.
Serve the brussel sprouts warm in a serving dish and garnish with fresh cracked black pepper and optional garnishes such as parsley or chives.