Shavuot: what's with the cheesecake?

(8) If HaShem is pleased with us, we will be brought into that land, and it will be our home, a land that flows with milk and honey.

(12) ...and when the Israelite women conceived, they would return to their homes. When they were about to go into labor, the women would go out into the fields and give birth in the apple orchards, as it is written: "I woke you under the apple [tree]" (Song of Songs 8:5). And the Lord Blessed be He would send an angel from the heavens who cleaned them and made them beautiful, just as a new mother grooms her infant, as it is written: "And as for your birth, on the day you were born..." (Ezekiel 16:4), and He grants them two round cakes, one of oil and the other of honey, as it is written: "And He [God] suckled Him [ The Children of Israel] with honey from the rock..." (Deuteronomy 32:13).

Sweetness drops From your lips, O bride; Honey and milk Are under your tongue; And the scent of your robes Is like the scent of Lebanon.

It is prohibited to fast immediately after the holiday of Shavuot. Ramah: And we do not say Talhanun from the beginning of Rosh Hodesh Sivan until the 8th day, which is after the post-holiday day (Hagahot Maimonides, Hilkhot Tefillah Umnagim). We have the custom to spread out plants on Shavuot in the synagogue and in houses, as a memory for the happiness of the receiving of the Torah. We have a custom everywhere to eat dairy food on the first day of Shavuot. And it seems to me that the reason is: It is like the two foods that are taken on the evening of Pesakh, a reminder of the Korban Pesakh and a reminder of the Korban Hagiga, so too we eat a dairy food followed by a meat food, and we bring with them two loaves on the table in place of the Mizbe'akh, and thus there will be a reminder of the two loaves that were brought on "the day of the Bikkurim."

Dairy foods - See Magen Avraham and I also heard in the name of a Gadol who said a correct reason for this: that when Bnei Yisrael stood at Har Sinai and accepted the Torah(When the 10 commandments were revealed, and through this all the parts of the Torah were also revealed to them, like that Rav Sadya Gaon writes, that the 10 commandments sustain the whole torah) and they went down from the mountain to their homes they found nothing to eat immediately except for dairy foods because for meat they would need much preparation to slaughter with a checked knife like Hashem commanded... And to clean out the strings of forbidden fats and blood, and to rinse and salt(the meat). Also to cook in new vessels because their previous vessels had been used to cook meat (that they now discovered was actually trief) had been used in the last 24 hrs (which is what is forbidden Biblically) so their old vessels were forbidden to them, therefore they choose on account of the time to eat dairy foods and we do this as a commemoration of this.

Every kind of flesh is forbidden to be cooked in milk, except for the flesh of fish and of locusts. And it is also forbidden to place it upon the table with cheese, except for the flesh of fish and of locusts. Fowl may be placed upon the table together with cheese but may not be eaten with it, the words of Bet Shammai. Bet Hillel say: it may neither be placed [upon the table together with cheese] nor eaten with it. Rabbi Yose said: this is one of the leniencies of Bet shammai and the stringencies of Bet Hillel . Concerning what table did they speak? Concerning the table upon which one eats; but on the table whereon the food is set out one may place the one beside the other, and not be concerned.

So too, the meat of beast or bird cooked with the milk of beasts or cattle is biblically not prohibited from eating; hence, it is permissible to cook it and to derive a benefit from it. It is, however, prohibited from eating it on rabbinic grounds, so that the people may not reach out beyond what is permitted and transgress the biblical meat-milk prohibition by eating the meat of a clean animal with the milk of a clean animal, since the literal meaning of the verse is restricted to a kid in its mother's milk only. For this reason, the sages have prohibited all meat with milk.