Sweet chestnut purée (crème de marrons) squeezed through a pastry bag into vermicelli and topped with chantilly to resemble France’s highest mountain. Invented in the mid-19th century (as per usual, claims of who came up with it first vary) Mont Blanc is especially popular in the winter as it’s on the heavy side.
Sometimes it comes on a meringue base, or with chocolate sauce. Or sometimes Mont Blanc means crème de marrons mixed with crème fraiche in a bowl.
There’s also a French company called Mont Blanc that makes puddings sold in tins or in refrigerated tubs in various flavours—only none are chestnut flavoured.
Images by Honio, User: Franki71