The Galette Andouille is a buckwheat galette folded around smoked andouille, and the andouille is the reason it has its own name rather than being a footnote to the standard Breton galette. A galette is a thin buckwheat batter poured on a hot cast-iron crepière, cooked until it sets and lightens, then folded around its filling and served flat. The filling here is andouille de Guémené, the Breton tripe sausage built from concentric rings of pork intestine, sliced to show its spiral cross-section, smoky and unmistakable. Warmed on the galette and folded in, it is a strong, specific flavor that the bitter, earthy buckwheat is one of the few wrappers that can stand up to.
The pairing is the whole craft. Buckwheat is not neutral the way wheat flour is: it carries a nutty, slightly bitter taste of its own, and against a mild filling it can dominate, but against the smoke and offal of Guémené andouille it reads as the right counterweight rather than competition. The galette is cooked thin and folded into a flat parcel, usually four edges turned toward the centre, so it is eaten with a knife and fork off a plate rather than carried in the hand, which lets the andouille stay sliced and layered rather than packed tight. It is hot-plate food, served the moment it comes off the iron while the bread still has its crisp edge and the sausage is warmed through, and it pairs the way most Breton galettes pair: with a glass of cider.
This is a Brittany specialty, and the andouille version sits inside the larger Breton galette tradition where the wrapper stays constant and the regional filling changes the sandwich's name. The variations are a question of what goes in the fold: ham and cheese and a soft egg in the classic, a grilled sausage in another corner, the smoked andouille here in Finistère. Those siblings, the buckwheat galettes and their wheat-flour crêpe cousins, are gathered under Crêpe & Galette Salée, and the Galette Andouille is its smokiest member: the one that asks the buckwheat to do the most work.