Chausson
A chausson is a puff pastry turnover, folded in half and sealed at the edge around a filling. The name is French for "slipper" and describes the characteristic half-moon shape.
The best-known version is chausson aux pommes, filled with apple compote. In France it is a bakery classic alongside the croissant.
Three technical rules apply. Seal the edge firmly but keep egg wash off the cut edge: wash that reaches it glues the layers and blocks the rise. Pierce or slash the top so steam escapes and the pastry does not burst. Use a thick, cold filling — a loose one boils inside and tears through the dough.
The top is traditionally decorated with shallow arcs scored with a knife tip, without cutting through.
Chill the shaped pastries before baking: cold butter in the layers gives a sharp lift on meeting the oven heat, whereas warmed dough spreads and loses its lamination.