My Favourite Cake

This is my all-time favourite chocolate cake from Four Leaves. I've bought this for Jerome's birthday before I knew how to bake and decorate cakes. Yes, I bought my favourite cake for Jerome so that I can eat it :)

What I love about the cake is between all the rich and smooth chocolate cake and chocolate moose, there is a crispy layer. Don't know what's that. The next time I eat this cake again, I'm going to 'dissect' it and find out exactly what it is. Going to try to 'duplicate' it at Sheryl's Kitchen :P Anyone knows what's that crispy layer?