The pain au chocolat (known as chocolatine in southwest France, a regional distinction capable of igniting fierce debate) is a laminated viennoiserie consisting of croissant dough wrapped around batons of dark chocolate, baked until the pastry shatters and the chocolate melts into flowing pools within. The base is croissant dough (détrempe of flour, milk, sugar, salt, yeast, and a small amount of butter, laminated with a beurre de tourage block through a series of turns). The lamination protocol is identical to croissants: the butter block (250g butter per 500g flour) is enclosed in the détrempe, then given three single turns (or two double turns) with 30-minute refrigeration rests between each turn, producing 27 layers (or more) of alternating dough and butter. After the final turn and a 1-hour rest, the dough is rolled to 4-5mm thickness and cut into rectangles of approximately 10cm × 15cm. Two batons of dark chocolate (55-65% cacao, specifically manufactured for boulangerie — bâtons de chocolat pour pain au chocolat, which are formulated to maintain shape and not burn at baking temperature) are placed parallel, one-third from each short end. The dough is rolled twice: the near edge folds over the first baton, continues to the second baton, then the far edge folds under, seam-side down. The finished piece should be compact and symmetrical, with the seam beneath. Proof at 27°C and 75% humidity for 90-120 minutes until the lamination layers are visibly puffy and the dough feels like a cloud when gently pressed. Do not egg wash before proofing (it seals the surface and restricts expansion); wash immediately before baking. Bake at 190-200°C for 15-18 minutes, with a brief burst of steam at loading for additional volume. The finished pain au chocolat should be deeply golden, with visible spiralling lamination layers, a shattering crisp exterior, and two distinct seams of melted-but-not-leaking chocolate within.
Croissant dough base with full lamination. Two batons of boulangerie-grade dark chocolate. Rolled twice to enclose both batons, seam-side down. Proof at 27°C/75% humidity for 90-120 minutes. Egg wash only before baking, not before proofing. Bake at 190-200°C for 15-18 minutes.
Chill formed pain au chocolat for 15 minutes before proofing to firm the butter layers. The two-baton method is traditional; for an even distribution, use chocolate batons that span the full width of the rectangle. If making from scratch, temper the ambient temperature: laminated dough work is best in an 18-20°C environment.
Using regular chocolate that melts completely and leaks out. Under-laminating the dough, producing a bread-like rather than flaky texture. Egg washing before proofing, sealing the surface. Over-proofing until butter begins to leak between layers. Baking at too low a temperature, producing a greasy result as butter renders slowly.
Le Larousse du Pain (Eric Kayser)