If you've been solving the NYT themelesses recently and you've found them disappointingly easy, hopefully this will give you the challenge you're looking for.
Pronto per iniziare?
per salvare progressi e statistiche sui cruciverba
Fun solve! Some very nice clues (31A was particularly great). (FYI in 35D, I think “truncated frustum” is redundant. "Conical frustum" is basically equivalent to "truncated cone" — with the truncating plane parallel to the base.)