Place the maftoul in a deep pan with the sugar, and add enough water to cover by about 1 inch (2.5 cm). Bring to a boil and cook the maftoul until tender; depending on its size, this should take 10-12 minutes. Drain the remaining water, add the butter, and stir over the heat for a minute or two.
Place the maftoul in a bowl and scatter over some more sugar, if desired. Scatter with the rose petals, serve, and eat straight away.