[MSL]

Egg fruit (Jidan-guo)

  It's a fruit. Its Chinese name is "鸡蛋果", which means "egg fruit" (lit. "chicken egg fruit").
 I ate 2 egg fruits. I like this fruit! A photo of one of these egg fruits: . (It is on the table.)

[MSL]

  Here is another (night-) photo of egg fruit (jidan-guo): .

[mlipure]

I have never seen this kind of fruit. Instead, I found a similar kind of it , guess what is it :-) ??

[SEO]

Of course it's a mango.

[JonusJay]

  I lived in Shenzhen for 7 years and I used to buy this fruit on the street, usually only saw it in February or March I believe. It tastes nothing like mango. It has a creamy mild but sweet taste that is heavenly. I like it so much that I brought some seeds back to California with me and plan to plant them someday.

BTW, if you've ever had mamey sapote (a central american fruit) it's similar in texture  and taste, but mamey also is not easy to find in stores. Luckily the Mexican store "NorthGate" in Escondido has it sometimes. Good luck!

[MSL]

 Good to know it.
 I tried different seeds in different places, in different periods of time. Well, the lesson I learned is: read well about the plant, before you put the seed/seeds. Because some of them need more sunshine others -- more shadow; some need more water, etc.
 I hope your experiment may be successful, because both Shenzhen city and California state are comparatively warm places with similar weather. Good luck!
 And, btw, welcome in this omnilogy forum (i.e. forum about everything). :)