Wash and rinse the brussels sprouts. Peel the loose, outer leaves. Trim the end, then cut brussels sprouts in half.
Heat a skillet on medium heat. Slowly cook bacon pieces until fat is released, but bacon is still soft and not crisp yet. Remove skillet from heat. Then add minced garlic, balsamic vinegar and stir until combined.
Place brussels sprouts piled in the middle of the sheet pan. Pour bacon oil mixture onto the brussels sprouts. Gently toss until the brussels sprouts are evenly coated with bacon oil. Spread the brussels sprouts into one even layer on the sheet pan. Season with salt and pepper.
Bake in oven for 20 minutes, then gently toss and mix the brussels sprouts.Bake brussels sprouts for another 20 minutes, or until the brussels sprouts are tender and bacon is crisp.Add additional salt and pepper to taste if needed. Serve warm.