Torchon means dishtowel. The technique: cure raw duck or goose foie gras with salt, sugar, white pepper, and a touch of Sauternes or Armagnac, then roll it tight in cheesecloth and poach it gently in stock or water below 70C. The lobe firms into a perfect cylinder, the fat redistributes, and the result is a clean, cold, sliceable preparation that needs nothing but salt, bread, and acid. This is the classical brasserie service of foie gras — older than the seared version, and arguably more honest about the ingredient. The lobe is doing the work. The cook is just shaping it. Done right, the texture is somewhere between butter and silk, and it should taste of duck, not of seasoning. The deveining matters as much as the cure. Pull the central vein and the smaller capillaries with the back of a spoon while the lobe is at 18C — cold enough to hold shape, warm enough to release the veins without tearing.
Cure for exactly 24 hours, no more. Over-cured foie gras tastes like ham. The salt should season, not penetrate to the core. Devein at 18C, not cold.