This is an excerpt from A Noble Boke off Cookry
(England, 1468)
The original source can be found at
MedievalCookery.com
To mak a Lampry in bruet tak a lampry and skald hym and rost hym on a gredirn then grind pepper guingere clowes and saffron and sethe it well and put pepper in the lampry and serue it.
Other versions of this recipe:
Lamprayes in browet (Liber cure cocorum [Sloane MS 1986])
Lamprays in brewte (Gentyll manly Cokere (MS Pepys 1047))
FOR TO MAKE LAMPREYS IN BRUET (Forme of Cury)