Rabbi Moshe Isserles mentions in the Shulhan Arukh, Orah Hayyim (670/2) the custom of eating cheese on Hanukkah and states the reason. This custom is already mentioned — as indicated in the Shulkhan Arukh — in the Kol Bo, a Halakhic compilation of the 13th-14th century and by Rabbi Nissim ben Reuben (14th century) in his commentary on Alfasi (tractate Shabbath).
The eating of Latkes on Hanukkah is, seemingly a more popular custom. There are different types of Latkes, depending on their ingredients. The latkes eaten by Jews on Hanukkah — as different as they might be — have one thing in common: They are prepared with oil.
We eat them in remembrance of the miracle of the Temple oil.
The eating of Latkes on Hanukkah is a very old custom. Moreover, the two Hebrew words for Latkes, Levivot and Sufganiyot (or the older form Sufganim) are not only two old Hebrew words, but they have been employed for centuries as names for the Hanukkah delicacies.
This does not imply that we eat the same Latkes, which Jews were eating on Hanukkah in the 12th or 13th centuries. Even nowadays the Latkes eaten on Hanukkah by different communities are not the same. Each generation and its own community has its own way of preparing its festival food, but the Hebrew names Levivot and Sufganiyot (or Sufganim) for the Hanukkah delicacies have remained constant.
The word Levivot occurs in the Bible, Samuel II 13:6. According to Rashi, ibid., they are prepared by stirring fine flour in boiling water and then in oil. Sufganim is of Mishnaic origin. The word which appears in Tractate Halla 1:4 is related to the word Sefog (sponge) A Sufgan is a sponge like cake (See Rashi, Pesahim 37a) According to R.O Bertinoro on Halla 1:4-5 Sufganim were made of soft dough, which was fried in oil and honey or cooked in water. The Biblical Rakik is translated by Onkelos Espog.
Now for some medieval sources in which Levivot and Sufganim appear as Hanukkah delicacies.
Kalonymus Ben Kalonymus (13-14th century) physician, writer, parodist and translator who lived in Southern France and later in Italy, writes in his Even Bohan that during Hanukkah “Respectable women assemble to prepare Levivot,” which are round and large. They also prepared from fine flour: Sufganim and Iskeritin.
Iskeritin like Sufganim are mentioned in the Mishna Halla 1:4. Rashi in his explanation of the word (Pesahim 37a) refers to the Targum of Tzapihit Bidevash (Shemot 16:31)a kind of honey cake. Both Rashi and R O. Bertinoro state that Iskeritin were made of very soft dough.
Iskeritin as a Hanukkah delicacy is also mentioned by Rabbi Maimon, Maimonides’ father. See below.
The Hebrew poet Immanuel of Rome (13th-14h century) an older contemporary of Kalonymus writes in the ninth Mahberet of his Mahbarot about Hanukka. He mentions the preparation of Levivot as well as of Rekikim, Tzapihit and Maaseh HaHavitim and Marheshet.
The Biblical Rakik, is as mentioned earlier, rendered by Onkelos Espog (a sponge like cake). For Tzapihit see the explanation of Iskeritin above as well as further on. Maaseh HaHavitim (Divrei HaYamim 1,9:31) and Marheshet (VaYikra 2:7) denotes food prepared in frying pans.
Many years ago, the late Rabbi Yaakov Moshe Toledano published in his miscellany “Sarid UFalif” a Hebrew translation of fragments of Rabbi Maimon’s (Maimonides’ father) Arabic book about the prayers. He writes that one must carefully observe all the customs. “On Hanukkah it is the custom to prepare Sufganim— these Tzapihiyot Bidvash,which the Targum rendered Iskeritin. This is a very old custom.We eat these, because they are fried in oil, which reminds us of the L-rd’s blessing…”
American Jewish Times (Lakewood) Dec. 22, 1995