Is it ok to use confectioner sugar instead of caster sugar for this recipe?
confectioners sugar is all I have so is it ok to do?
You don't have regular granulated sugar that you could put in a coffee grinder or food processor.
Confectioner sugar usually has a declumping agent in it, often corn starch.
I'd wait until I could go to the grocery...but if you are feeling experimental it could be interesting. I suspect the texture will suffer.
I wouldn't -- superfine is coarser than confectioners' -- so the measurements won't be the same, and it may well come out too sweet.
You can whizz regular sugar for a second or two as Scoutmaster suggested, or wait til you can get to the store.
No--as others have noted, confectioners sugar has cornstarch in it which gives it a completely different texture and it's so different in weight that it's tough to make the same measurement as superfine sugar. Also, I don't know if the sugar crystals in confectioners sugar are big enough to contribute to the structure of the cupcakes. You know how the directions say to cream the butter and sugar together until light and fluffy? I think with confectioners sugar you'd probably end up with something more like sticky and gummy.
I have used confectioner sugar (powder sugar) instead of granulated sugar. Just beware that confectioner sugar has a different density than caster sugar.
eHow suggests to use 1.75 volume of granulated sugar for confectioner sugar. I find this to be quiet reasonable. I have just measured 1/4th of a cup of granulated sugar and confectioner sugar and they were:
1/4th cup of granulated sugar: 54 g
1/4th cup of confectioner sugar: 32 g
In your case, your recipe actually askes for superfine sugar. So I will guess something about a 1 cup of confectioner sugar in place of 3/4 cup of superfine sugar.
It is also true that confectioner sugar has a small amount of cornstarch to prevent lumping/caking: 3%. However, it is my opinion that the contribution from this small amount of cornstarch won't make a huge difference. I mean, you have 1-1/2 cup worth of all purpose flour in your recipe, and you may have between 1/2 teaspoon to 1 teaspoon worth of cornstarch if you used confectioner sugar. In my experience, such small amount of cornstarch did not make any noticeable difference for me.