Here’s a detail that trips people up: many classic, mass-market pineapple cakes use a filling that blends pineapple with winter melon (冬瓜). Winter melon makes the filling smoother, sweeter, and less stringy, and historically it was cheaper. That’s the familiar, mellow “pineapple cake” a lot of travelers grew up tasting.
In response, a wave of bakeries now make “tu fengli su” (土鳳梨酥)—cakes filled with 100% local pineapple, which is more tart, fibrous, and intensely fruity. Neither is “better”; they’re different experiences. If you want bright, tangy, real-pineapple flavor, look for the all-pineapple style. If you prefer something softer and sweeter, the classic blended filling is lovely.