Help 9 inch sponge recipe

[Bigfoot1]

Need to make a 9 inch sponge for Dd Birthday. Hoping to make one large one and cut it in half (only have one 9 inch tin!)
Anyone give me quantities and timings?
Was going to use 50:50 butter/stork and do chocolate so substitute some flour for cocoa powder.......

Round or square?

Round

I’m usually fairly competent but i’ve decided 8 inch won’t feed 17..... but don’t want to end up with tons of left over cake.....

4 or 5 eggs.
170, and probably about an hour would be my best guess.

Thanks Sandland. My guess was 4 eggs and 160 for 55 mins....
Any advances?
(Isn’t mumsnet great!)

I use 4 large eggs to do 2x 8 inch. 5 won’t do 9 inches. Hang on and I’ll work it out.

A 9 inch round is 20% bigger than an 8 inch so 5 eggs would do it. I’d use 6 to be sure through. Equal
Weights of eggs (in their shells), butter, flour and sugar. Wrap the tin in folded newspaper and bake at 160 for about 1 hour 20 mins.

Yup Titty is right - I'm just about to make a cake now in this method - two 9 inches.

Weigh 5 or 6 eggs in shells. Same weight of butter, caster sugar, and sf flour. I find a few drops of vanilla essence adds flavour, and I normally need a couple of tablespoons of milk to get it to the consistency I want.

Bale at 155 for about an hour - stick skewer in to check done.

I make cakes like this very frequently.

a few drops of vanilla essence adds flavour,

Extract. Never essence. :)