I think this is the first time I make a cake that is not baked but fried. It is called Gâteau de Crêpes in French or Mille Crêpes. Essentially it is a stack of 15-20 plus very thin crêpes with pastry cream or jam spread in between. It is not served at breakfast as Americans do with pancakes but enjoyed as a dessert.
I was a bit shocked to see the price tag of a 9 inch Mille Crêpe Cake sold in a fancy cake shop in New York City (Lady M $75-80). The ingredients are nothing extraordinary. But it does take skill, patience and time to fry those twenty plus pieces of paper thin crêpes. It took me about 30 minutes to fry a batch. After that, just layer with whatever flavored pastry cream you prefer. I picked mango for this one, but you might like strawberry, dark chocolate ganache, vanilla or green tea better. The batter of this French crêpe is much thinner than our regular American pancake batter. Just remember to fry it as thin as possible for best texture.