In deepest, darkest France there is a village called Pthivier which has given its name to this pie. I admit it is a complicated recipe but make no apology for that. Traditionally it was filled with frangipane but was also made as a savoury. The one shown here comprises three layers inside; a potato cake, a round of salmon pate and a round of goat's cheese.
Originally the pthivier was a sweet dessert pie filled with frangipane. I haven't tried this but would love to hear from anyone who does.