you might need to make the sponges slight thinner and layer them though, for fear that the middle won't get cooked at the same rate as in the smaller tin.
Take the tin that you usually use for the cake mix you usually use, fill it up with water to the level that you normally fill it up to and then poor it into a measuring jug.
Then do the same with the new tin...... and compare the amounts. Then calculate the recipe as per the ratio.
Does that makes sense?
Help! I make sponge cakes all the time, the usual 6oz butter, 6oz sugar, 6oz flour and 3eggs. However, I have just bought a big tin 12" x 16" and I can't work out how much mixture I need to fill it. Can anyone help me scale up?
TIA