I feel like the blog is becoming just a redirect to Food Lab posts... but Kenji's list of six kitchen myths is really good and pretty eye opening to most of us I'd bet. I knew about the "salting beans" one because I'm a Cook's Illustrated guy, but both the "don't need a giant pot of water for pasta" and the "moist cooking method" ones were genuinely surprising to me.
UPDATE: From the comments of the above post comes a very interesting post from the French Culinary Institute's technical guys (bookmarked!) that says you're better off soaking sliced mushrooms in water and cooking them in a very crowded pan! Hurrrrwhaaaa!? I definitely need to try this.