I want to try IMBC but noy sure which recipe to use. I saw one that says to use caster sugar, what is caster sugar, I never heard that term before?
You were probably looking at a British recipe.
It's just a UK term for superfine white sugar. It has a finer grain than the regular store-bought granulated sugar we get here in North America.
You can buy it as "jelly sugar" or "superfine sugar" here....or just use a recipe that doesn't use it. Martha's is great:
Here's an excellent step-by-step how-to for you too:
Thanks for the grat info Antonia