EASY & QUICK PINEAPPLE PIE RECIPE  

Chinese social media probably, so douyin or WeChat (or another app I’m unaware of)

I’m also curious to know if this is also true

it's just a running gag

All the so-called trending recipes are just those recipes that's heavily proliferating in the Internet. These Pineapple Pie recipes is variant of Philippine Pineapple Pie. Many channels really like to credit grab all kinds of recipes they got in the internet, very common amongst East Asians Channels like Chinese, Korean, Japanese, Vietnamese and those Western like American, Canadian.