She won our hearts as Grace in Will & Grace, but in Birthday Candles Debra Messing shows more range as Ernestine who moves methodically through her birthdays from 17 to 107 showing the sweep of her life during the course of the play. The scenes of the Roundabout Theatre Company’s production take place during her birthday tradition of baking her own cake. Six actors play 12 characters with aplomb – bringing Ernestine’s extraordinary-yet-ordinary life to the stage. This quiet playing shows the existential meaning in small moments – the loving mom (Susannah Flood) and troubled daughter, the haple…