A cake or food which is made extremely rich and is basicly uneatable and unpleasant to eat. The maker of the cake shows that they still need some lessons and to be taught properly how to make a nice cake. The cake can be dry in a number of ways such as making it well in advanced of intending to eat it, making it a week before you will eat it. Another way to make it dry is to place dry things on the top of it such as chocolate finger biscuits or Maltesers. The end result is that you have made something which is unpleasant to eat.
Person 1: Check out that Cake
Person 2: That looks so dry
Person 1: It tastes dryer than the sahara desert
Person 2: Wow that must be a Dry Cake