Boil the potatoes. Peel, mash and prepare mashed potatoes with just a little butter to make them harden (no milk or water). Most of the other products (without the mayonnaise and cheese) are finely chopped and mixed with the mashed potatoes.
Set some mayonnaise and cheese aside to decorate the cake on top. The resulting potato mash is spread onto a cake plate or platter and shaped like a cake.
The top is coated with the mayonnaise that has been previously set aside. Decorate with the remaining products and grate cheese on the very top. Serve and cut like a cake.