You can just pour the ganache directly over the stack of crepes (see how
). Sam wanted a thicker topping, a consistency between a fudge and a ganache, so she put the bowl of ganache in a bowl with pieces of ice. Ganache thickens as it cools and that is why it has to be used the moment it reaches the desired consistency. Sam stirred the ganache until it thickened just so then spread the chocolate on the cake.