how do i make royal icing?

[MakeAnotherCuppa]

i know i need icing sugar and egg whites but not sure how much of each

this is a good easy guide

675g/1½lb icing sugar

3 free-range egg whites

3 tsp lemon juice

1½ tsp glycerine

extra egg white to thin icing if required

But I would suppose it depends on how big the cake is...

Can't see that there's an easy sort of formula to it, but it looks like 1 egg white to 200g icing sugar (ish)

fab, thanks, just 1 more question... whats 4 cups in oz?

1 cup = 8oz i think.

but may be worth a quick google to check

thanks shirley, the other link had cups not g/oz,

making a ben and holly castle for DD so think i'll need alot!

Recipe from here

I'm not sure but you should be able to see how much icing this recipe makes.