I made a delicious new chocolate cake recipe today from a Bees of Bloomsbury cookery book. It said to use either one 10 inch diameter tin (I assume a deep tin) or two 7 inch round sandwich tins. Now that is definitely not right - I used water to check the different volumes. So I used two 8 inch round sandwich tins. The mixture cooked well except for being slightly crisp on top. Should I have used two 9 inch sandwich tins? The cake as it is, is fine, but it is such a lovely recipe that I would like to do it justice next time! I had a problem once before with recommended tin sizes and got in touch with the cookery book author. She congratulated me on getting it sorted out myself?