Take.. half a pound of bunacre, and make a Cake thereof
To make a Horse follow his Master, and find him out and Challenge him amongst never so many people.
Take a pound of Oat-Meal, and put to it a quarter of a pound of Honey and half a pound of bunacre, and make a Cake thereof, and put it into your Bosom next to your naked Skin, then run or labour yourself till you Sweat, then rub all your Sweat upon your Cake, then keep him fasting a day and a night, and give it him to eat, and when he hath eaten it, turn him loose, and he shall not only follow you, but also hunt and seek you out when he hath lost you or doth miss you, and though you be environed with never so many, yet he will find you out and know you, and when he cometh to you spit into his Mouth, and anoint his Tongue with your Spittle, and thus doing he will never forsake you.
By "An Experienced Farrier," found in The Horseman's Week-End Book.
Anyone tried it? Though of course, you do need to know what Bunacre is, and I haven't had any luck finding out so far.
Comments
There's also another OED reference, not in the dictionary but in a library search of its other texts, has this information from a book of British place names for the similar word "Benacre": ‘Cultivated plot where beans are grown’. OE ban + æcer.
So maybe something made of beans or pulses?
Lunarce seems to be as nonexistent as Bunacre however. According to this forum post (caution: this site is NSFW), this is a misprinting of "lunarie":
The recipe is quite straightforward, but the tricky part is the "halfe a pound Lunarie". (the actual writing 'lunarce' is result of a broken wooden type, the dot over 'i' broke off - this work predates Gutenberg with iron types!)
There are two herbs of this name. One is so poisonous that it would kill any horse it's given to, almost instantly. Additionally, it's mostly unused in magical recipes. The other though, was considered an essential magical component of lots of different important mysterious recipes. It's a small fern, maybe 4 inches tall, and quite rare. Not extremely rare but appears as single plant of 2-4 sprouts, maybe 2-3 such plants per square mile of a forest, never forming groups of any significant size. This means gathering the mentioned amount of half a pound of this fern is nearly impossible - this would be 200-500 sprouts. Additionally the fern is a real bitch about growing it in pots or other controlled environment and under protection in many countries, so any bigger organized action of gathering it would certainly get to the officials and get you in trouble.
I'm not sure about the publication predating Gutenburg, but Lunaria (the plural of lunarie) exists though it hardly seems rare or difficult to obtain. I don't know if it's poisonous though.
Probably made the name Bunacre up so he could sell it for three times the price of common or garden lunaria.