Kouign-amann is a Breton cake. It is a round crusty cake, originally made with bread dough (nowadays sometimes viennoiserie dough), containing layers of butter and sugar folded in, similar in fashion to puff pastry albeit with fewer layers. The cake is slowly baked until the butter puffs up the dough (resulting in the layered aspect of it) and the sugar caramelizes. The effect is similar to a muffin-shaped, caramelized croissant. This fine example was from @laboulangeriesf in the Noe Valley District.