Slice bacon and pan fry bacon, but only partially cook your bacon, it will finish cooking in the oven, remove bacon from pan, and add diced red onion to the pan. Cook red onion until just softened.
Wash Brussels sprouts and slice in half, remove any brown leaves. On a cookie sheet add sliced Brussels sprouts, partially cooked bacon, red onions along with pan drippings and mix well. Pour olive oil over the Brussels sprouts and stir until the Brussels sprouts are evenly coated. Roast for approximately 25 minutes, sprinkle with kosher salt and add fresh cracked pepper before serving.