I have that recipe on my farmer. I can't remember if this is a recipe that you automatically get or not, but I got all the recipes that you don't get automatically from the novice or expert vendor, so if you don't already have it, it should be for sale from the expert farmhand.
The superior fields I use are in Hobbiton, so that's where I would have gotten it.
It should have been automatically granted.
If you've been around for several months, it was granted when Golden Shire Taters were removed from the Cook vendor. I'm not in game, so I don't know what level the recipe is.
Like the post above you suggest, especially if you read the previous posts aswell, you'll find that Golden Shire Taters are a auto-granted Master-tier vegetable.
One post suggests they are artisan recipes and buy them from the expert farmhand. One other post says that she made master farmer and has then but didn't say anything about getting them automatically. And another says they should be automatically granted but doesn't say what level. So, you'll forgive me for asking to confirm since there were three posts with basically three different answers.