scarola

It's broad-leaf curly chicory lettuce—not Belgian endive (witloof), which causes endless confusion, especially as its other name, indivia, does also mean Belgian endive.

It's the classic green used in pidoni, but you might encounter it stuffed (imbottita), with bread crumbs, olives, capers, cheese...

The scarola di Bergamo, cultivated in the hills above the city and noted for its inner white leaves, is in the Slow Food Presidium.