this is very dangerous. in this day and age of endless spam, your email can easily get caught in some spam filter. add to that how busy the dean's inbox probably is at this time of the year, and your message may never be received.
does your friend have the dean's home phone number and address instead? hang out in the bushes outside the dean's dining room. once you see that the dean has finished dessert, use your cell phone to call the house and make your plea. be sure to mention the dessert item by name and how tasty it must have been. the dean will take this as a sign that you are a very perceptive individual. but also be sure to bring some raw steak in case the dean releases the hounds.