So, what does a more traditional take on this question look like? Check out the short video answer provided by the United Synagogue of Great Britain (Orthodox):
To read my take on the background to eating dairy on Shavuot, the Ledger link is here (Scroll down for my answer on eating dairy).
But the best answer I've read this year was the one I received from my father. Encouraged by what is clearly the Jewish tradition of having an endless number of answers to this vital question of Jewish practice, he decided to add a few more of his own. Enjoy!
Qu: Why do we eat cheesecake on Shavuot?
A: There are many answers, most , if not all, of them wrong. Perhaps the most credible answer, in the traditional Yiddish style, is "Why not?' Always answer a question with a question. This sharpens the mind and frays the nerves.
Another answer is that one day it was Shavuot and Rev Nachman was standing before his students wearing a white robe. With his pale skin he was barely identifiable against a pale background. One of his students was heard to remark: "Doesn't he look just like a bit of cheesecake" and this memory has been preserved ever since.
There is a lot more to Rev Nachman than a chair.
Another answer is that in olden times the harvest at Shavuot was celebrated by eating doughnuts. These doughnuts were the original kind, with a ring of dough sprinkled with sugar and a hole in the middle.Our sages and thymes tells us in an unconvincing, yet mystical, way that the ring represents all the Jews in the world and the hole ( which is not only in the middle but also occupies the surrounding space) is where God lives.
So no matter where you are, if you look, you will find God.
One day, around 1400 CE, a woman was buying doughnuts for Shavuot and said in a feigned middle-Eastern voice: "Ach, these fried doughnuts gives me heartburn; same with KFC. Haven't you anything else"
"How about a bit of cheesecake?" replied the baker. "Ok, I'll try a piece" said the lady.
And she never had heartburn again, dying peacefully the following day.
"A miracle" exclaimed the baker and Jews have been eating cheesecake on Shavuot ever since in the hope that they, too, might be delivered from heartburn.
Although this rarely happens, they have not stopped trying.
(Not a Rabbi)