Cut up the agar-agar strips, wash, then soak in water for about 10 minutes. Bring water to the boil with the screwpine leaves. Add the agar-agar and cook till dissolved. Put in sugar and bring to the boil. Remove half cup of agar-agar solution. Add colouring and pour into rose-and-leaves portion of the mould.
Add sago to the rest of the agar-agar and cook till transparent. Remove from heat, add in milk and stir in the beaten egg white. Use a whisk to beat well. Pour over set roses and leaves. Leave aside then chill well in the fridge.