Clarice Lispector, it's great and the portuguese is not a hard one. Her more famous book is "a paixão segundo G.H."
Also, this conto
from João do Rio is beautiful and the portuguese quite normal:http://www.releituras.com/joaodorio_homem.asp
You can find interesting texts in this link, most with normal portuguese, but I guess they are mostly short stories:http://www.releituras.com/
A writter which usually writes in a much different portuguese, which can be from little to extremely tough to read, is Guimarães Rosa. But maybe you should give it a chance. It's tough for native portuguese speakers to read it(i.e. Grande Sertão: veredas), It's equally tough for old erudits as to teenagers, once the issue is not that he writes difficutly in formal portuguese, but that he created his own way to deal with the language. But once you get used to the style, it gets easy; maybe it can work the same with non-native speakers.
His more famous short story, however, is written in a much more normal portuguese than most of his writtings:http://www.releituras.com/guimarosa_margem.asp
I intended to make a very literal english translation of it:http://siruiz.wordpress.com/2010/03/07/ ... the-river/
This story has a much less complicated portuguese than "Grande Sertão: veredas" or "Tutaméia", or even "Corpo de Baile", and following the english translation I made, you might find many passages that sounds weird in english. They are maybe not mistakes I made, I tried to translate literally many passages which also looks very weird in portuguese, until you get used to Rosa's style.