Chrysophyllum gonocarpum

Known in Brazil as “aguaí” (aguahy), it is a native of South Brazil in all forests, so it can stand low temperatures close to 32 F. The fruit is roundish, yellow to orange-skinned with white very sweet flesh and 1-2 small seeds. The tree is about the size of an abiu (Pouteria caimito) when cultivated. The foliage is very ornamental, being the leaves long and thin more or less shaped like C. imperiale (but without the torns), to which it is related. 

If you like Chrysophyllum gonocarpum, you might also like Chrysophyllum sp. "Golden Nugget" or Chrysophyllum argenteum "Caimito de mono"