After Neo talks to the Oracle Neo walks into the hall where morpheus is sitting. look at the cookie in Neo's hand, it has a bite taken out it. but when he goes to take a bite out of it, it is whole, and the bite he takes out of it matches the vanished bite.
If you go back to the kitchen scene you can see that the cookie has a flatened edge when he pickes it up off the glass platter. When he carries the the cookie out to where Morpheus is, it is this flattened edge - not a bite that you see. However, when he bites the cookie the flattend edge is gone. . . unless he turned the cookie in his hand between shots.
I also notice that the cookie is crunchy. If it was just baked, shouldn't it be soft?? And, you would think, hot as the oracle just removed them from the oven.
I never noticed the cookie bite, but I did always notice how the Oracle said, "almost done," and then takes them out of the oven right after she says it. If they're ALMOST done, then they shouldn't be ready to come out of the oven yet! I don't think it's really a slip-up, but I always found it funny.
For the greatest mind in all of the Matrix, she sure can't cook. Neo damn near broke his teeth off eating that thing. Personally if I went to see the Oracle would see me pitch that damn cookie into the trash can twenty minutes before I showed up.