Ingredients :

• Potatoes — Choose Charlotte or Amandine. Not Bintje—they turn into mash and you lose all texture. The Charlotte holds up well to pre-cooking and absorbs the sauce without disintegrating. 800g for 4 is a generous portion.
• Smoked turkey sausage — We use a smoked turkey sausage instead of the traditional Morteau. Look for a whole smoked sausage, not pre-sliced circles in a tray—those dry out during cooking. If you find a wood-smoked version, even better: you’ll taste it in the dish.
• Cancoillotte — A melted cheese from Franche-Comté, quite liquid, with a mild and slightly tangy taste. Plain or with garlic depending on your mood—garlic adds a bit more character. 150g seems like little, but this cheese grows in volume as it dilutes in the cream.
• Light crème fraîche — Used to thin out the cancoillotte. Light works perfectly—the cancoillotte already brings enough fat. Exactly 10cl: enough for a coating sauce, not enough to drown the gratin.