The Internet term "天菜" means a strengthened version of "Ta is my dish" and is usually used to emphasize that someone's appearance or character is very appealing and makes people feel good. It is mostly used in Taiwan Province of China and is not very popular in mainland China.
The origin of the term "heavenly dish" can't be traced back to its origins, but it was used by He Gui in "Happy Camp". And now Tian Cai is generally used to describe the very best, not you can't mean. And also from the "heavenly dish" derived from the "heavenly dish girl", and "heavenly dish girl" means "this girl is my dish, is my favorite type! ".