To make it really fair so that one isn't fresher than the other, you need two people. One is at Jazz Kitchen. Actually, 3 people. One at their outside counter place where I got (and didn't enjoy) them. One at the actual JK restaurant. One at Cafe Orleans.
Synchronize watches and order at the same time (not sure how you could do this). Hope that they are all made at the same time. Put all into the same type of container (obviously, white paper bag is best, yes?) so make sure everyone has the same thing. Then all walk towards each other, so when you meet it's been the same amount of time.
THEN taste-test.
It's possible I've thought of this a little bit too often.