by Suelle » November 28th, 2019, 3:35 pm
I think you're probably right for cakes that are beaten well - the sugar has time to dissolve into the cake batter during mixing, as well as cooking. Enough not to notice the difference, anyway, unless you're Mary Berry or Prue Leith.
Possibly also OK for cakes that cook a long time, such as fruit cakes - some recipes use brown sugar anyway. Certainly things like gingerbread cakes, where you're dissolving the sugar anyway don't need caster sugar either.
I think caster sugar is useful for things that are mixed quickly and have little moisture - eg scones and biscuits. I go further than this and use icing sugar to sweeten pastry.
My mother always used granulated sugar and no-one complained, but we knew nothing different.
It probably boils down to how much of a perfectionist you are. The difference might be noticeable to some, but is it enough to matter? (Having said that, I do use caster sugar)