Could I use caster sugar instead of granulated sugar for Nigella's Vanilla Fudge?
Nigella's recipe for Vanilla Fudge uses a combination of milk, condensed milk, butter and granulated sugar to give a traditional, slightly grainy fudge. Granulated sugar is used as there is a large quantity of sugar in the recipe and usually caster sugar is more expensive then granulated sugar. Outside of the UK granulated sugar tends to be slightly finer and caster sugar can be more difficult to find.
However it is possible to use caster sugar if you wish to do so. Caster sugar has smaller crystals and will dissolve more quickly than granulated sugar. Whenever making fudge make sure that you watch the pan carefully at all times and check the mixture once it has turned a golden brown colour to see if it has reached the soft ball stage. It is better to check earlier rather than later, as you can always return the pan to the heat and boil the mixture for slightly longer if it has not quite reached the correct temperature.