After running around like a dumbass forever... it's not in Winterspring, and don't try and quest for it.. unless your an idiot.  Just go to Stonard in Swamp of Sorrows and learn it from the Master Alchemist there. 
Remember though, you must be at least 280/300 in Alchemy to learn it.
This can be learned from master trainers. I know it can be learned from the one in feathermoon. I'm looking at it right now. Hopefully this clears some stuff up for you.
This item is now deprecated. You can learn to make Major Healing potions from your faction's Master Alchemist, Rovgar in Stonard or Kylanna Whisperwind in Feathermoon.
I just flew to Feathermoon Stronghold and learned the Major Healing Potion from Kylanna Windwhisper, the Master Alchemist. It only cost 1g 80s and you have to be at least 275 in Alchemy. I spent a long time in Everlook, and NEVER found it at the alchemist there.
Ok so i tried for like a week to get the stupid recipe in winterspring. Finally I paid a mage 3g to port me to Shattrath city (originally to get the highest level in alchemy) and low and behold u can actually just learn this recipe for 2g from the alchemy person there. You can also learn the Volatile Health potion at 300 here as well.
.....reads above notes....ok so i got bored reading the comments on where to get it so i never scrolled to the bottom until now...oh well its not like no one ever repeats info on here. :-)    Happy Healing
I got it as soon as I clicked on her and so I wanted to see how long it would take for it to reappear and it took 1h 30m or give or take to have it show back up again.
superior healing potion - over 1 hr greater mana potion - over 50 mins the damn major healing potion recipe - over 1hr 10 mins the legendary mooncloth pattern -  existence-doubted
*note that it's "over". Was waiting there for a total 1hr 10 mins
I got really annoyed that it wasn't spawning at Everlook, then I read here where someone had posted that it could be learnt at Master Trainer a few minutes after I checked. Im kicking myself that I wasted almost 3-4 Hours waiting for something that wasn't there ! :(
I am baffled by the misinformation on this subject. Could Blizzard have changed something? This potion can be purchased from Rogvar the Master Alchemist Trainer at Stonard in the Swamp of Sorrows. He is up the stairs in the building next to the wind rider master. Do not be confused and try to perchase it from the alchemy supplies vendor. she never has it. You must go to the trainer to get it, NOT the vendor. I looked for this for a month. Don't waste your valuble time. Go see Rogvar in swamp of sorrows. 
This, along with Mighty Rage Potion, Elixir of Brute Force, and Greater Arcane Elixir, can be trained by the Master Alchemist, for about 1g80s each. (Horde's Master Alchemist is in Stonard, Swamp of Sorrows.)
She has it. The problem is that certain players like to buy off these harder to get recipes from vendors and put them up at the auction house for insane prices. :(
apparently since BC was released she no longer sells this .. it can be learned from a trainer in Outlands. havent confirmed this, but its what i hear. :shrug:
nvm .. this is trained at Master trainer pre-outlands. Since BC release it is no longer a vendored recipe from Winterspring as you can learn it from your trainer for about 2g(?). hope this helps .. oh yea, believe its skill 280 to learn also!
Have been trying to get this for a day or three now.. no luck so I bought it off the AH. I feel so ashamed now for indirectly supporting those <*****> that seem to camp her for this recipe.. oh well.
A small convenience fee is fair, obviously because of the time wasted. However, most farmers don't do it to save time for the buyer, they do it because they want to inflate the price 1000% and make money off of a system that is intrinsically flawed because it gives rewards for focussing on making money from something that does not belong to them.
The difference between farmers and playes are Farmers do not need the item they do it for financial gain only thus halting the progress of other people well earned skill tree's. Not in the spirit of fair play. In fact the server we play on, has soo many lvl 60's its hard to make any money now. ok for those already at 60, not great for the rest of us :(
Well i was just about to go to bed 2 mins ago i had shut wow and this page happened to be opened behind it...i hadn't read through it i just had wanted to know where the potion was being sold...so i decided to give it a quick read about the peeps complaining about farmers, whilst doing so i read about the 2 people who alt-tabbed back into the game and just happened to get it...so i thought ok..give it a go...re-opened wow, went and checked with her...and...she had it!  so make sure if you want it and she didn't have it last time you checked...go and check again now :P
really going to bed now.
ohh and on another note....if people are stupid enough to buy for insane prices in the AH then its their fault...its a trading economy...happens in WoW..Happens in the real world...deal with it dudes..yeah, bed...G'Night (Happy WoWing)
andydzman, I was standing in front of the vendor and she didn't have it, so I hopped on here to try to see how often it respawns. I saw your comment, and thought to myself "What the hell, i'll check" and alt tabbed back in. Sure enough, she had it, and I had only been standing there about 5 minutes. Go figure. :P
I just got the recipe.Well it wasnt that hard and the advice of geting there early is the best i got.So i recomen that if u cant be onl early in the morning give some instrucions to some1 who can and let him buy it for u.... Best of luck in buying the recipe....it is most needed one.
anyways, to sum it up. The vendor is in the first house to left after entering the town Everlook at winterspring. To get to everlook you have to travel or dying through the timbermaw [53-54] cave at northern end of felwood. An alternative is to have goblin engineering and use the transporter to teleport yourself in. (If you get killed using that, please don't sue me. :P) There are both alliance and horde flight master at Everlook so once you are there you will always have an easy access route.
The recipe is limited supply and a rather lengthy respawn time. If you really want the recipe then camp the vendor by all means. If you feel there are too many competition from the opposite faction, just kill the other player and run out before the guards kill you.)
I just clicked on her to get the Major Healing Potion.  It was there, but to find out i dont have the money for it.  I borrowed soem money from a guildmate, went to mailbox, came back and it was gone. Now, the question that i have seen before still hasnt been answered. How long does it take for her to have it again? Thanks for your time : )