Help, I am planning to make my daughter's birthday cake as a two layer white chocolate mud cake covered with ganache. One of her friends is allergic to egg so  I used 2tsp baking powder, 1 tsp water and 1 tbsp oil as a replacement for one egg per cake, and cooked it for a bit longer. It came out very moist, collapsed in the middle, and cracked when I took it out of the pan to cool. I am hoping I can salvage it by freezing and applying syrup and a ganache crumb coat before the final ganache frosting, and I'll make another batch for the actual cake (this is a trial run). I also read that mud cakes should be left to cool completely in the pan before turning out so I"ll do this next time. My question is should I be using another type of egg replacer eg would the addition of cornstarch help? I don't want to buy a whole box of commercial egg replacer (which I've used before with great results) just to make two cakes. IS there anything anyone can suggest? help!!

Hi, 

Try using flax meal as a replacer. 

You can follow the instructions from here:

http://www.egglesscooking.com/2008/10/15/egg-replacement-event-flaxseed-meal/

HTH!