This simple dish, best known in the Veneto (the region surrounding Venice), is based on a mixture of pancetta and butter, but lightly reduced cream can replace the butter and even the pancetta. This approach need not be limited to peas; other delicately flavored green vegetables such as asparagus tips, baby string beans, or baby green onions or leeks can be quickly blanched or boiled and tossed with the pasta. Parsley is called for in the traditional recipe, but other herbs such as chervil or chives can be used to give this dish a vaguely French touch.