In a bowl, mix egg and sugar until evenly blended.
Add in flour, mix well.
Pour in coconut milk slowly while continuing to fold the mixture, add in salt and few drops of food colorant.
Take putu ayu mould (or any small, personal serving cake mould), line with cooking oil. Place grated coconut on the base of the mould, while carefully pressing it. Pour mixture until mould is ¾ filled.
Place moulds into steamer, steam on medium heat until mixture is slightly dry. Turn off heat, take out from steamer.
Steam on medium heat so the resulting putu ayu won't rise too much. This recipe has been tested in Dapur Rasamasa (Rasamasa Kitchen).