Tourin

Tourin is the everyday soup of southwestern France, documented above all in Périgord (the Dordogne) and across Gascony, Lot-et-Garonne, and the Tarn-et-Garonne. The name appears in many spellings — tourin, tourain, tourrin, touril in the Rouergue, touri in Béarn — and derives not from any word for stirring but from Occitan tourar, 'to cook', itself from Latin torrēre, 'to grill or parch'; the same root gives Spanish turrón. The most famous form is the garlic tourin, but onion (tourin à l'oignon) and tomato (tourin à la tomate) versions are equally traditional, and there is a wedding tourin, the tourin des noces, that was long served to newlyweds. In the Périgord it was indeed the custom to bring a tourin to the bride and groom on their wedding night, and the soup is also eaten to revive after a long village feast.

Long, gentle cooking turns the garlic mellow and faintly sweet — nothing like the raw, acrid bite a clove gives off cold — so a soup carrying twenty cloves still tastes round rather than fierce. The broth is silky and savoury from the egg, the bread underneath soaks soft and almost dissolves into it, and a last splash of vinegar cuts through the fat with a clean, sharp lift. Done well it is warming and gently rich; done badly the garlic stays harsh and raw, or the egg is dropped into boiling broth and seizes into ragged curds, turning the soup into thin garlic water dotted with overcooked egg.

Sweating the garlic slowly in fat is what tames it: the volatile, pungent allicin compounds responsible for raw garlic's harshness break down and cook off with heat, while gentle browning and slow cooking coax out sweeter, rounder flavours. The thickening rests on the egg. Yolks are first slackened with a little vinegar or a ladle of hot soup, then stirred back in off the boil — tempering raises their temperature gradually so the proteins set into a smooth, velvety body. The cardinal rule is to keep the soup just below a simmer once the yolk goes in: at a rolling boil the egg proteins coagulate too fast and curdle into scrambled threads. The whites, by contrast, are trickled in deliberately so they do set into fine ribbons. The vinegar at the end balances the richness with acid, and the stale bread soaks up liquid to bulk and bind the bowl.