No quantities are given "as they are not important; Concia can be prepared to be more less piquant, according to taste, by increasing or decreasing the quantity of herbs and spices. It freezes beautifully in a tightly closed container, but it must be used within a few days if stored in the refrigerator or after thawing, being a rather perishable food. Eggplant was also prepared as Concia in Rome, but its texture is less desirable than eggplant.
Trim off the ends of the zucchini; then cut each one in half; slice each half thinly lengthwise and place slices on paper towel to dry for several hours or overnight. Fry in hot olive oil in a single layer until golden brown on both sides. Arrange in layers in glass, plastic or porcelain container and season each layer with small amounts of garlic, basil, salt and pepper, and a sprinkle of vinegar. Cover the container and store in the refrigerator at least several hours before using. The flavour will be enhanced if you turn the Concia as a block inside the container a few times while it is marinating to allow the juices to seep through.