So it turns out I've got a lot more detailed information than I thought on authentic medieval food and recipes. In the book Daily Life in Chaucer's England, in the chapter on food, there are about 15 recipes taken directly from late 14th century primary sources.
They're taken from 3 late 14th century primary sources, the Diversia Servicia, Forme of Cury and the British Library Manuscript Royal 17 A iii. It contains recipes for the following dishes:
Ground Beans
Cabbages in Pottage
Turnips in Broth
Fried Spinaches
Salad
Egurdouce of Fish
Blanc Manger
Mustard (for a Roast)
Tarts of Flesh (Pork Dumplings)
Tart in Ember Day
Tart de Bry
Apple Tarts
Hippocras
Mead
Bread
It is interesting to note that medieval recipes are very imprecise compared to a modern recipe. I will transcribe one of the recipes here:
Tarts of Flesh
"Take boiled pork and grind it small with saffron; mix it with eggs, and dried currants, and powder fort and salt, and make a foil of dough and close the stuffing therein. Cast the tartlets in a pan with fair water boiling and salt; take of the clean flesh without eggs and boil it in good broth. Cast there powder douce and salt, and serve the tarts in dishes, and pour the juices thereon.
- Excerpt from Daily Life in Chaucer's England, page 200
No measurements are ever given for any of the ingredients in the actual primary sources.