Believe it or not, I am only just now collecting certain Cooking recipes! I know, right? I figured if I'm still working my way through obscure content like this, surely others are as well. So I've put together a guide to help folks who haven't gotten to these "hidden" goodies yet.
There are two recipes available to cooks who've mastered the Way of the Brew (you must also be level 87 or higher).
The first item is a recipe for Banana Infused Rum, which is a novelty drink that instantly makes you "completely smashed" for 30 seconds. It also turns you into a Hozen pirate. Unfortunately you are stunned while the effect is active and your screen is quite blurry. Even so, it could be entertaining as a way to pass down time during raids.
Finding the recipe for Banana Rum may be a bit of a challenge. It spawns from a barrel in Nayeli Lagoon, above the cave at the far east side of the southernmost island. This is the same spot where you can find Spriggin (one of the rare Pandaria mobs). There is a large ship jutting out high above the cave, which is where Spriggin and the barrel can be found. All you have to do is fly up and click the barrel:
The brown barrel on the right side is the one you're after. If you fly up here to check and there are only three barrels with no brown one on the right, then the recipe has not spawned yet. Here is another pic with the right-most barrel missing:
Comments on Wowhead seem to indicate that the barrel is set to autoloot, so make sure you have room in your bags for the recipe. I got a stack of five flasks as well, so you may need to have two free bag slots. I also saw a few folks claiming that this recipe can be looted even without the required Way of the Brew and 87 character level. I have confirmed this with my Mage (above) who currently has a Cooking skill of 372.
The second recipe is called Four Senses Brew and it is found in Kun-Lai Summit. To reach it, you'll need to fly to the very top of Neverest Pinnacle (NE of Winter's Blossom). There's a lore object up there as well as a statue of a Pandaren. You may have to wait for the tablet to spawn, which you can see here:
The brown rectangle in front of the statue is the item you need. When you loot it, the recipe will be inside:
The mats for both of these recipes are quite high. To make the Four Senses Brew you'll need 3 Ironpaw tokens and two stacks (200) of Red Blossom Leeks. That's a heavy commitment to one item, especially something with a rather vague tooltip. Since the materials are worth 500-1000 gold, I decided to go ahead and make it to see if it was truly useful. When crafted, you really get just one of them (I was hoping that was a tooltip error). After you use it, you get a 5 minute buff called Four Senses Brew and your screen looks like this:
It may not be super-obvious, but there is a haze effect on my screen. I flew around the Half Hill area a bit (down to Galleon and back) but didn't notice anything different around me. Commentary on Wowhead does not shed any new light on what this brew might enhance for you. These are still worth grabbing for completion's sake. They also count toward the "Relic Hunter" set of achievements!