I thought this one was going to go even faster! I had finished the bottom half in under 5 minutes, but clearly the upper half had my number.
I broke in at 22A: Fiver (ABE), which gave me CASABA, because what other fruit has a B in that position? I didn't get any purchase in the NW from that, but the D implied at the end of 3D gave me the ever-present ADAR at 25A. I wasn't holding out much hope at this point for the puzzle with two so hoary answers already in the grid.
I started to enjoy myself a little more when I saw MOHS (thinking of Horace's father), and then with 33A: One whose work hours may involve minutes (STENO), and SPINETS. I liked the clue at 33D: Terse cop order, more than the answer (SPREADEM), but I liked both at 36D: Rush-hour subway rider, figuratively (SARDINE). And the SW also had NEURO in it, so much happiness ensued.
50A: Chicken or mashed potato (DANCECRAZE) is one of my favorite clues today. I'm not sure that "mashed potato" shouldn't be capitalized in this sense. In any case, I had the whole first word in place from the crosses before I looked at the clue, so the answer was fairly obvious.
54A: They're never required (ELECTIVES) is fine. It's clever having OBSOLESCE intersect with PASSE. Otherwise I wouldn't much want to see that word in the puzzle, as I feel it's not in common parlance at all.
After that, I stared at the puzzle for a while. Even with ACTII being a gimme for me (love La Boheme soooo much... sounding like a fan-girl here... a fan-girl for Puccini!), it took me a while to get purchase here. I love IONOSPHERE - a great word. 27A: Ballet supporters (TOES) is brilliant. I finished the puzzle at the cross of GOAPE and ROSH. That's a tricky crossing, for sure, but perfect for the time of year.
1A: Like Blofeld in Ian Fleming's "You Only Live Twice" (SCARFACED) is a little twisty. I think the adjective is appropriate, but I don't think it's what you'd say in conversation. "His face is scarred," perhaps. The term "Scarface" has such a strong association with the Pacino film, it's weird to see it this way referring to another person. I'll give it a B. But the puzzle was definitely enjoyable.