Pirate ship cake

[babybouncer]

I'm doing a pirate ship cake for ds' birthday. I need to make three square cakes to cut up and make the right shape, but the only recipes I have are for round cakes. How do I convert? Or does anyone have a recipe for plain cake I can use?

If you want to do it strictly mathematically

The volume of a normal round cake (assuming it's top isn't too peaked but a gentle curve) is the average height (take a half-way point between the height at the edge of the circle and the height in the centre) multiplied by (pi)x(radius)x(radius) - "Pi R squared" (pi is 3.14ish and R is the distance between the centre and the edge)

The volume of a square cake is simply the multiple of (side1)x(side2)x(height)

So, (i) calculate the volume that a round cake made with your normal recipe would occupy. (ii) calculate the volume of square cake you want to make

Divide your answer to (ii) by your answer to (i) and that is the amount by which you need to multiply the quantities of each ingredient of your normal recipe to make the right amount.

If you want to make life simpler

Just make 2 or 3 times your normal recipe for round cakes. Put mixture in each square tin till it is about half way up the tin side to allow for rising, and put any leftover mixture into bun cases.

Slightly less strictly mathematically (since the granularity is "number of eggs" so there is no point being too precise ) - according to my cake books, a recipe for an 8" round cake will make a 7" square one. Does that help?

Make sure you choose a nice dense cake as you will be carving it and don't want it to fall apart - and also, chill or freeze the cake before carving.

Good point stealthsquiggle - both about the fraction-of-eggs and about the density - a normal spongecake recipe tends to be too crumbly for cutting into accurate shapes, doesn't it.

There's a great recipe for a dense cake in use itie=UTF8&qid=1339488810&sr=8-4 this book called "inmates chocolate cake" - it's fantastically easy beacuse all you need to do is stir together all the dry ingredients then whisk in the wet ingredients and cook. We used it for DS's christening cake because its dense texture makes it good for slicing small slices which don't crumble. Happy to post the recipe if you'd like me to but I've seen this recipe book in 90% of the kitchens I've visited so my guess is you probably have it.

no idea what went wrong with that link but it seems to work anyway