Have you ever wondered what that British cookbook meant by “castor (or caster) sugar”? I certainly have!
So, I looked it up on Merriam-Webster.com and found:
: finely granulated white sugar
But, my question was how that compares to powdered/confectioners’ sugar. So, I kept searching and found this helpful picture and tutorial on instructables.com:
So, there you go! It’s about the texture of fine sand – so right in between granulated and powdered sugar.