It is served as part of a starter course, or with a salad, or with boiled meats.
The vegetables can include carrot, cauliflower, celery, onion, zucchini, etc; all are chopped up coarsely. The vinegar can be red or white wine vinegar.
There is a distinct American version, which hails from Chicago. It differs from the original version, in that oil replaces the vinegar.
It was evolved from the original version by Italian immigrants, becoming popular there in the 1920s. It is mostly used as a sandwich condiment, particularly on Italian beef or sausage sandwiches in Chicago, though of course has many other uses.
Chicago-Style Gardiniera may use vegetables such as bell peppers, carrots, cauliflower, celery, olives, sport peppers, red pepper flakes, etc.
The oil can be canola, olive or soybean, or a mixture.
You can buy both the Italian version and the Chicago-Style version in jars in stores.
“Giardiniera” means “woman gardener” in Italian.
Another Italian name for this, “Sotto aceti”, means literally “under vinegar.”