I had the same problem as I was just searching for the drink recipe, from the choices with the addon. I then started doing a food recipe search as well and was able to find the recipe easily then.
So if you did what I did doing the drink recipe search it will never show up as the recipe is listed as a food recipe and should show up for you then in guild stores.
Yeahhhhh I've been searching for this damn recipe off and on since the patch for vouchers launched and I have awesome guidl store and I can't seem to find it anywhere....
Mutagem - AD Stamina Nightblade - Prefect
Mutagentleman - AD Magicka Templar - Palatine
Mutageneticist - AD Magicka Sorcerer - Corporal