Theme: Repetitive Syllables
Since Thursday puzzles do not have titles, it’s up to the solver to figure out the theme. For me, the “Aha!” moment came after I filled in the latter half of 19-Across (cantata). Even then, until I checked Rex Parker, I didn’t realize that not only do the initial three syllables repeat, but so do the final two syllables.
19A. Bach work performed at the Moulin Rouge? = Can Can Cantata
37A. One spotted at the Rodeo Drive Taco Bell? = Chi Chi Chihuahua
51A. North African counterpart to an Italian Baroque sculptor? = Berber Bernini