For gratinated chard stems, wash the chard, cut into 10 cm long pieces, blanch the stems for 5 minutes, the leaves only for 3 minutes. Drain and sauté in half the butter, add salt.
Preheat the oven (220 °C, grill function or top heat). Whisk milk with flour and nutmeg and pour to the chard.
Add 3 tablespoons of Parmesan cheese and 1 heaped tablespoon of breadcrumbs and continue to cook briefly on a low heat.
Then pour this mixture into a greased baking dish sprinkled with breadcrumbs (1 tablespoon).
Sprinkle the remaining amount of Parmesan and breadcrumbs on top, spread the remaining butter on top and gratinate at 220 °C for just under 10 minutes.