Drizzle olive oil in pan, coating the bottom. Turn on heat to medium and place Brussels sprouts on the flat side down in the oil.
After sprouts have cooked for about 10 minutes they should look nicely golden brown. Flip at this point and let cook on the rounded side for at least 5 minutes more until they brown on this side too.
About a minute before you take the sprouts off the heat, drizzle the balsamic vinegar over them. The sprouts will soak up the delicious flavor and the heat will caramelize the vinegar slightly. Plate and enjoy!