Gratin d’Endives à l’Ardennaise

Belgian endive is a winter staple in France, one of the few greens (though actually it should be snowy white) that continues all winter long. That’s because it is grown indoors, in the dark, so the leaves stay bleached as if they were underground. Once they are on the grocery counter, however, endives are open to the light, so the leaves begin to curl, turning green and bitter. So for crispness and the best sweet taste, go for all-white endives and remove any spoiled leaves. When baked in a