The Medieval Cookery website hosts or links to a large number of medieval and medieval-adjacent cookbooks transcribed online--some in the original language, some in English translation, some in other modern language translations.

Because medieval recipes can be...funky...it also wonderfully hosts a list of reconstructed recipes that adapt the medieval text (typically included at the bottom) into a modern-style recipe with amounts, exact ingredients, and so forth.

Happy cooking and happier eating!

Certainly on the more modern end, but these are recipes from American history.