If I have a recipe for a 5 egg cake mixture...

[SparklingTwilight]

and it makes a 24 cm diameter cake, which the recipe reckons serves 12, how many eggs do I need to fill a minimum of 26 fairy cake cases?

I reckon 5 eggs should do it. If you’re talking proper old fashioned fairy cake size, not the bigger cupcakes which have crept in everywhere.

Fairy cake, or cupcake cases? They are very different sizes!

My recipes for an 8 inch cake tin (double layer cake) will do 12 cupcakes or a single layer traybake.

Your recipe is for a 9 inch tin, which has 81/64ths of the area of an 8 inch tin, so I would expect it to do approx 15 cupcakes.

Not sure what proportion fairy cake cases have Vs cupcake cases which is where I get stuck, but assuming they're quite a lot smaller, I think you'd get away with either that 5 egg mixture, or upping it to 6 eggs.

I don't know. Probably more like cup cake cases then, I bought the baking form about 3 years ago.

2 eggs does 12 small fairy cakes, or 6 muffin sized cupcakes.

Post a pic of them next to the baking tin you’ll use them in. With perhaps a baked bean tin or something for scale! Then we can help check.

What is the rest of the recipe?

Some recipes are egg heavy and you will get a bit of a different sponge

I expect that recipe will make 26 fairy cakes. Small cases. Not muffin cases.

400g tin of tomatoes.

I can make 12 fairy cakes with 2 eggs, so I reckon you’ll get 26 out of 5 eggs.

That's a muffin case, but you don't need to fill it.
I'd say 5 eggs would just about, but slightly skimpy, do those.

Very flash pan and hob there, by the way.

I agree, don’t fill them and it’ll stretch to them

Can you fill a fairy cake case with water and see how many mls it is. 1 tblsp is 15ml so you can just count them.

Then fill the cake tin up and pour into a measuring jug.