In a medium bowl, combine the roasted brussels sprouts with the cilantro stems, leaves, and mint leaves. Toss well with the dressing and transfer to a plate in a low heap so that most of the herbs end up near the top. If you still need to do other Thanksgiving prep, tossing the brussels sprouts, herbs, and vinaigrette together until you're ready to serve — this will prevent the brussels sprouts and herbs from getting soggy.