OH MY- I ADORE Yamashita Tomoko but never came across someone who really knew her works!!! So yes, I second this recommandation. And one of her works is getting adapted into anime!!!
I also second Harada, Scarlet Beriko and Asumiko Nakamura!
As for me… One of my favorite BL is Oni to Tengoku by Oyoshikawa Kyôko and Aga Naomi, but lately I found out this amazing BL called Ore to Atashi to Shinsekai by Kouda En, that is both cute and angsty, with a perfectly well balanced amount of sexy, and soooo touching. Sadly, only a few chapters are translated, with 3 volumes (on going) in Japan. I've read all of them, and I can't recommend it enough!!!
Also not my favorite and a little less famous, but a really good author that always makes me laugh is Sangatsu Masao. All of their works, with NO exception, have characters with glasses, and they're all funny in a very unexpected way, yet very cute and calming.