I have a well-tested (triple layer) 9-inch carrot cake recipe with lots of texture (3 c. carrots and 1 c. each raisins, walnuts, pineapple and coconut.) My question is how to adjust the recipe to make a (triple) 10-inch cake.  I don’t want to sacrifice the height of the layers any further.  The dry ingredients is based on 2 c. flour, the liquid includes 3 eggs, 3/4 c. buttermilk and 3/4 c. oil (in addition to assoc. pineapple juice).

Would it be as simple as increasing flour by 1/4 c., adding an egg and being a little more generous with the fruit?

Hi!

To go from 9” to 10”, you’ll havea to increase everything by 25%—except, I think, baking powder.  If you have soda, increase that, but since you’re increasing the size of the cake, you’ll want a stronger structure, so you’ll want less baking powder (proportionately) to achieve that.  I would think simply leaving it at the 9” quantity would do it, but rules really kind of change after you go beyond a 9” size, so you might find youll have to experiment.  Also, the cake will take longer to cook, so you will probably want to use cake strips to keep the edges from drying while waiting for the center to cook.  I’d try one layer to be sure it works before doing all 3 layers.  That’s just a couple of thoughts, but maybe someone else with more experience in this area can help!

—ak

This may sound utterly unconventional, but the quick and lazy method I would test (rather than using math and multiples, etc) is to take your original recipe and divide it in half because you know the original recipe would fill two 10” pans and leave a little extra (I would guess a 5 or 6” round).  Then make 1.5 times the recipe; this should fill 3 10” round pans.  (this might just be what Anne in NC is doing by multiplying things by 25%!!) Then I’d make this amount and see how it goes.