Ignoring dishes with New World ingredients, do we know how conservative food traditions are in Europe? Would a 12th century Earl of Huntingdon have eaten anything similar to an English person in the 20th century?
Was continental cuisine significantly different from English food? If so, was it appreciated in England as it would be in modern times? Was there a significant North African influence on northern Spanish cooking?
This is a question I can kind of answer for you. http://medievalcookery.com/recipes/ is a compiled list of meals/recipes that have been collected. I can't tell you if one was a noble dish or a peasent dish. I've tried several of these dishes though. Makes for a good a good weekend.
Well I can recommend a book instead:
http://www.amazon.com/Time-Travelers-Guide-Medieval-England/dp/1439112908
There is chapter dedicated to food in those times and worth noticing that many recipes you can from book or documents from those times will probably be for nobles, merchants or clergy of good economic position. Peasant's menu will be far simpler, repetitive and sometimes scarce.