Trim/clean Brussels sprouts, then cut them in half if desired (or you can leave them whole). Arrange on a baking sheet and toss with olive oil. Sprinkle with plenty of salt and pepper and roast at 375˚F degrees for 25 to 30 minutes, or until brown.
Combine balsamic vinegar and sugar in a saucepan. Bring to a boil, then reduce heat to medium-low and reduce until very thick, about 15 to 20 minutes.
Drizzle the balsamic reduction over the roasted sprouts, then sprinkle on dried cranberries. Toss and serve immediately.