Silly Christmas cake questions that are keeping me awake

[Barbarara]

if I change the type of fruit in a recipe, are there any rules/advice about this, eg should I have a minimum ratio of vine fruits or does it matter?

When I substitute one fruit for another, should I measure it by weight or volume?

If I add nuts should I take out a similar weight/volume in fruit to compensate or does it matter?

Not an expert but I do sub various fruits/nuts (BIL is allergic) in my Christmas cakes. Varying the type of fruit will vary the taste, so whether you want a minimum amount of vine fruits depends on the taste you are aiming for. I tend to work by weight not volume when subbing fruit, though if the substitute has a particularly strong taste (e.g. apricots) I would use less than the fruit I was substituting and make up the difference with something less strong. I sub the nuts on my favourite fruit cake recipe with the same volume of glacé cherries which seems to work fine.

With regards to the fruit I think you can use any dried fruit really : I use prune, figs, raisins, cranberries, glace cherries, sultanas. Hate currants so don't bother with them. What other fruit other than vine were you thinking of adding?

For nuts I suppose it depends how many you want to add to the recipe - half a cup won't make much difference, 2 cups might!

I substitute by weight. I hate peel so instead put in the same amount of dried cranberries using the Nigella recipe.

If you reduce the amount of fruit, you will be reducing the amount of sugar, so it probably won't keep as well. Once you've reduced the fruit too much, the cake part will go stale and you won't have the compensation of all of the fruit getting more luscious the longer you keep it.

If you don't want to put a lot of fruit in, don't adapt a Christmas cake recipe but find a "semi rich fruitcake" recipe which should give you the instructions on how long it will keep for. Just after World War II, dried fruit was hard to come by, so such recipes were quite common.

Brilliant advice. Thanks everyone!

If you use other fruits that are sweeter/sourer just adjust the sugar though if it is to be iced don't worry about adding extra sugar. If adding any fresh fruit watch the moisture content

I would try to swap things with a similar water content/absorbancy, although probably don't need to do that if you're a bit more flexible on coming times and are feeding it.