Mont Blanc (or Montebianco, as known in Italy) is a dessert made with puréed, sweetened chestnuts, topped with lightly whipped cream. Due to its resemblance to a snow-capped mountain, this dessert was named after Mont Blanc, the highest mountain in the Alps, shared by France and Italy - the latter could also apply for the sweet version, whose origin is still disputed between these two countries.
The third, and most probable theory is that it was invented sometime in the mid-19th century in Paris, as an elaborate upgrade of some previous, similar desserts. The traditional French version is made with puréed boiled chestnuts flavored with milk, cocoa, vanilla, rum, sugar, and a dash of salt, decorated with whipped cream, additionally enriched with a crispy meringue base, which the Italian version does not have.
It was the French version that inspired a certain Mr. Sakota to create Monburan, the Japanese take on this dessert. He tasted it during his visit to Paris and was so overwhelmed that he opened a pastry shop in Tokyo offering the Japanese variety, made with chestnuts in syrup.