|Alternative name(s)||Napoleon, gâteau de mille-feuilles, vanilla slice or custard slice (UK, Australia)|
|Place of origin||France|
|Main ingredient(s)||Puff pastry, pastry cream, powdered sugar|
Traditionally, a mille-feuille is made up of three layers of puff pastry (pâte feuilletée), alternating with two layers of pastry cream (crème pâtissière), but sometimes whipped cream or jam are substituted. The top pastry layer is dusted with confectioner's sugar, and sometimes cocoa, or pulverized seeds (e.g. roasted almonds). Alternatively the top is glazed with icing or fondant in alternating white (icing) and brown (chocolate) stripes, and combed.
The exact origin of the mille-feuille is unknown. François Pierre La Varenne described a version in Le Cuisinier françois, 1651. It was later improved by Marie-Antoine Carême. Carême, writing in the early 19th century, considered it of "ancient origin".
Traditionally, a mille-feuille is made up of three layers of puff pastry, and two layers of crème pâtissière. The top layer is coated with a sprinkling of powdered sugar. In later variations, the top is glazed with icing, in alternating white (icing) and brown (chocolate) strips, and then combed. Today, there are also savory mille-feuille, with cheese and spinach or other savory fillings.
Variant names and forms 
According to La Varenne, it was earlier called gâteau de mille-feuilles (English: cake of a thousand sheets), referring to the many layers of pastry. Using traditional puff pastry, made with six folds of three layers, it has 729 layers; with some modern recipes it may have as many as 2,048.
The variant name of Napoleon appears to come from napolitain, the French adjective for the Italian city of Naples, but altered by association with the name of Emperor Napoleon I of France. The Larousse Gastronomique does not mention the Napoléon, although a gateau napolitain is listed, with a note that while the cake itself is not often seen, small biscuits known as fonds napolitains are still made, decorated with butter cream or conserves. There is no evidence to connect the pastry to the emperor himself. In France, a Napoléon is a mille-feuille filled with almond flavoured paste.
The authentic Australian Napoleon slice has pastry on the bottom, a layer of strawberry jam, a layer of sponge cake about 3 cm thick, another layer of jam, a layer of cream topped by a layer of puff pastry and spread with vanilla icing.
In Italy, it is called mille foglie and contains similar fillings. A savory Italian version consists of puff pastry filled with spinach, cheese or pesto, among other things. Another important distinction of the Italian variety is that it often consists of a layer of puff pastry with layers of sponge cake as well (e.g. from bottom to top, puff pastry, sponge cake strawberries and cream and then puff pastry).
In the United Kingdom, the pastry is most often called a "vanilla slice" or a "cream slice", but can, on occasion, be named "mille-feuille" or "Napoleon" on branded products.
In Russia, Napoleon can be made with either pastry cream or "sweet butter." It typically has more layers than the French archetype, but the same height.
In Canada, mille-feuille is more commonly named 'gâteaux Napoléon,' or 'Napoleon Slice,' (in English Canada) due to the country's long French history. It is sold either with custard, whipped cream, or both, between three layers of puff pastry. Almond paste is the most common flavoured variety. There is a French Canadian way where the mille-feuille is done with graham crackers instead of puff pastry, and where pudding replaces the custard layer.
In Sweden as well as in Finland, the Napoleonbakelse (Napoleon pastry) is a mille-feuille filled with whipped cream, custard, and jam. The top of the pastry is glazed with icing and currant jelly. In Denmark and Norway, it is simply called Napoleonskake.
In Hungary it is called "Krémes". Its version "francia krémes" (French Napoleon) is topped with whipped cream and caramel.
In Belgium and the Netherlands the tompouce or tompoes is the equivalent pastry. Several variations exist in Belgium, but in the Netherlands it has achieved an almost iconic status and the market allows preciously little variation in form, size, ingredients and colour (always two layers of pastry, nearly always pink glazing, but orange around national festivities). The cartoon character Tom Poes by Marten Toonder is named after the tompouce.
In the Spanish milhojas, the puff pastry is thin and crunchy. They are often far deeper than solely of three layers of the pastry, and reach up to .5 feet (0.15 m) tall.
in Philippines, it is called Napoleones (Na-pol-yo-nes); and is composed of 2 layers, with pastry cream or custard as filling, topped with sugar glaze.
In Iran, the pastry is called "شيرينى ناپلئونى" (Shirini-e Nâpel'oni, literally "Napoleonic Sweet Pastry") after Napoleon Bonaparte. It consists of thin puff pastry and often topped with powdered sugar.
In Greece, the pastry is called "Μιλφέιγ", which is the transcription of the word mille-feuille using Greek letters. The filling between the layers is cream whereas Chantilly cream is used at the top of the pastry.
An annual competition for the best vanilla slice baker is the Great Australian Vanilla Slice Triumph held in Ouyen in western Victoria. Judging criteria include "when tasted, should reveal a custard with a creamy smooth texture and a balance of vanilla taste with a crisp, crunchy pastry topped with a smooth and shiny glaze/fondant".
- The name is also written as "millefeuille" and "mille feuille".
- André Guillot, Vraie Cuisine légère, Éditions Flammarion, 1992, republished in 2007 ISBN 978-2-08-202542-3 (in French). The counting of layers was reported in Compte-rendu du Séminaire n°32 de gastronomie moléculaire (December 18th, 2003) from the French Society of Chemistry, see Compte-rendu (in French).
- Larousse gastronomique, p702; the mille-feuille is mentioned, page 667, and credited as a late 19th-century creation.
- "Travel news - The Great Australian Vanilla Slice Triumph". Ninemsn. 2006-07-20. Retrieved 2007-01-06.
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