This is an excerpt from Liber cure cocorum [Sloane MS 1986]
(England, 1430)
The original source can be found at
Thomas Gloning's website
Blaunche sawce for capons. Take blanchid almondis and smal hom grynde, Temper hom with verius, þat is hor kynde, Powder of gynger, and kast þer to, And messe hit forthe, þen hase þou do.
Other versions of this recipe:
SAWSE BLAUNCHE FOR CAPOUNS YSODE (Forme of Cury)
Sauce blaunche for capouns y sode (Fourme of Curye [Rylands MS 7])
White sauce for capons y-sode (Two Fifteenth-Century Cookery-Books)