You might be interested in the Medieval Cookery site, which links various facsimiles, transcriptions, and translations of cooking instructions from medieval and early modern manuscripts and printed texts. Some of them are even available in modern English!

If you are looking for more modern-style guidance for your own use in the kitchen, with measurements and such, you'd have better luck with Amazon.

Happy feasting!

I think you would be very interested in The Good Wife's Guide. Written in the 14th century, it's essentially a handbook for an upper class medieval woman and details the things she is expected to know and be able to do around the household.

It also includes a list of medieval dishes and recipes. Be warned though, medieval recipes are quite different from modern recipes in that they are much less detailed and precise.