Cake mix quantity help please

[BobsTaintedLeftLeg]

I'm making a 7 shaped cake by cutting up a rectangle slab cake.

It's a roasting tin I'm using that's 12in by 9in and roughly 2 in deep.

Cakes is going to be a chocolate vanilla marble cake.

Then basic icing job!

I'm having trouble trying to work out the amount of mix I need.

Can anyone help me please?

I would just make up two batches of three egg mixture and then tip it in until it was enough. But I am bad at maths!

If you have a standard round tin, fill it with water and pour it into the tin you're going to bake with. Repeat until full, then multiply your mix by the same amount. (an 8 inch round tin takes a 3 egg mix) you do need a more substantial cake than a Victoria sponge though, a Madeira is better. Its easily adjusted - 50g of each ingredient (butter sugar and flour) to each egg. So a 4 egg mix would be 200g of each. Add a splash of milk if the mix is too thick.

Thank you, I don't have round tins unfortunately.

I mainly make loaf tins or slab cakes for the kids, it's easy and quantity is a must with my bunch.

I'll try simply doubling my usual mix, can't have to much cake can you.......