 It is named after the French town of Pithiviers, where the dish is commonly assumed to originate.The filling is always placed as a lump in the middle of the bottom dough layer, rather than spread on it, to prevent it liquefying and leaking during baking.The pie is traditionally finished with a distinct shine to the top of the crust, by egg-washing beforehand, or by caramelising a dusting of confectioner's sugar at the end of baking, or both.