What is brioche?

Brioche is a bread of French origin that is similar to a highly enriched pastry, and whose high egg and butter content (400 grams for each kilogram of flour) give it a rich and tender crumb. Chef Joël Robuchon described it as "light and slightly puffy, more or less fine, according to the proportion of butter and eggs." It has a dark, golden, and flaky crust, frequently accentuated by an egg wash applied after proofing.

Brioche is considered a Viennoiserie (a baked item of goods made from a yeast-leavened), in that it is made in the same basic way as bread, but has the richer aspect of a pastry because of the extra addition of eggs, butter, liquid (milk, water, cream, and, sometimes, brandy) and occasionally some sugar.