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!!