A crisp piece of bread or pastry hollowed to receive a savoury filling:we had mushroom croustade with a hazelnut topping...
Nowadays croustades are considered old-fashioned in France; they may still be encountered on buffet tables at grand receptions, or as an accompaniment to drinks.
There were also dense slabs of chocolate fondant, and an apple croustade with a light, frilly crust that melted to butter in your mouth.
There is a wonderful recipe from that region for a croustade that encases apples and prunes in Armagnac.
Origin
French, from Old French crouste or Italian crostata 'tart' (from crosta 'crust').