Sufganiyot in Halacha:
*Typically, Sufganiyot are deep fried in oil, similar to French fries, hence lending it its name, which means a sponge like dough that has absorbed oil. A typical bakery purchased Sufganiya can be assumed to be deep fried unless stated otherwise. The laws below refer specifically to this type of Sufganiya, which carries special laws due to its deep-fried state. One who eats a baked Sufganiya, which has been recently catered for the diet friendly community, would need to follow all of the laws relevant to Mezonos bread, or of bread that is baked in a small amount of oil, but not deep fried.
It is a Jewish custom [which is Torah] to eat foods that are cooked with oil, during Chanukah. This custom is not mentioned in Poskim. Nevertheless, one is not to belittle any Jewish custom, as this custom dates back many generations, as testifies the father of the Rambam. The reason behind this custom is to cherish the miracle which took place through oil, and hence we eat fried foods on Chanukah. Another reason recorded behind why we specifically deep fry dough is in order to recite an after blessing of Meiyn Shalosh, in which we mentioned the altar that was re-inaugurated on Chanukah. The Alter Rebbe, and other Chabad Rebbeim, were accustomed to hold a family Chanukah party, called Latke event in its honor.
May a woman cook Sufganiyot or Latkes after candle lighting?
The before blessing of a deep fried, or jam filled, Sufganiya is Mezonos.
Blessing during meal: One is to recite the blessing of Mezonos upon eating a typical Sufganiya [deep fried and/or contains jam] during a meal, if he is eating it for pleasure purposes. If, however, one is eating it for purposes of satiation, then a blessing is not to be said.
After blessing if ate large amount: Deep fried Sufganiyot retain the before and after blessing of Mezonos and Al Hamichya irrelevant of how much one eats. [However, baked Sufganiyot can become Hamotzi and require Birchas Hamazon if one eats over a certain amount, just as is the law by all Mezonos bread.]
One is not required to wash hands prior to eating Sufganiyot even if they are wet from the oil, unless they were deep fried in olive oil. Typical store purchased Sufganiyot are deep fried in the cheapest available oil, and certainly not olive oil. [However, one who dips his Sufganiyah in tea or coffee, is to wash his hands beforehand without a blessing, as is the law by all dipped foods.]
Heating up on Shabbos:
A typical Sufganiya which contains jam inside of it is not to be heated up on Shabbos, due to the possible cooking prohibition relevant to the jam. [If the Sufganiya does not contain jam inside, then if it is completely dry, it may be heated up on top of another hot pot.]
There are various Kashrus worries relevant to Sufganiyot and they thus must contain a reliable kosher supervision to permit its consumption.
The Kashrus of the ingredients: The seemingly innocent ingredients of a Sufganiya indeed contains substantial Kashrus worries. These worries include: 1) Some places may use flour that is required to be checked for insects; 2) Some places may use oil that derives from excess lard as is common in some places in Europe; 3) Some places may use jam that is made from non-kosher glycerin; 4) Some places may use non-kosher alcohol that is added to the dough.
Hafrashas Challah: One is to perform Hafrashas Challah without a blessing on the dough of the Sufganiyah, if one is making a sizable batch that reaches above 1,250 grams of flour. A blessing is not to be recited even if the amount is much larger than the above, being that the dough is deep fried. [One who plans on baking the dough, is to follow the same laws as any baked product.]
Bishul Akum: Sufganiyot are deep fried and are therefore subject to the laws of Bishul Akum and not Pas Akum. It is hence forbidden to be cooked by a gentile just as is the law by the cooking of any other food. Thus, Kashrus agencies must ensure that their Sufganiyot follow the standards required for Bishul Yisrael. [According to Ashkenazi custom, it suffices to have a Jew simply turn on the flame even if a gentile does the frying. However, according to the Sephardim, a Jew must enter the Sufganiyot into the oil.]
 Shaar HaMoadim p. 117
 Letter of Rabbeinu Maiman, father of Rambam, printed in Nitei Gavriel 51 footnote 16 and Minhag Yisrael Torah in name of Koveitz Serid Upalit“One is not to be lenient in any custom, even if it is a light custom, and everyone is obligated to make a festive meal and rejoice to publicize the miracle that G-d did for us on those days. Now, the custom has spread to make Sufganiyot, known in Arabic as Spingim. This is an old custom being that the dough is kneaded with oil in commemoration of the miracle. Rabbeinu Nissim writes in Megillas Setarim that all the customs of the Jewish nation including this custom should not be belittled …as the prophet has stated “Al Titosh Toras Imecha”; Sheireis Yisrael Shaar Hazmanim p. 101; See Sefer Maiy Chanukah of Rav Yitzchak Ratzabi p. 55 that in Yemen they were not accustomed to eat deep fried foods or Sufganiyot, and this only began when they arrived to Israel.
 Halichos Shlomo Chanukah p. 319 in name of Kesav Yad of Rav SZ”A
 Hayom Yom 28th Kisleiv
 From the letter of the law, it is permitted to cook and do other meal preparations. [Or Letziyon 4:41] However, some write that it is best to refrain from the above during the first half hour. [Piskeiy Teshuvos 670:2] Practically, so seems to be the proper custom, to avoid all work at all in order to properly contemplate the Chanukah miracle during that time, as writes the Levush.
 Shalmei Moed p. 244 that so was the custom in the home of Rav SZ”A
 Seder Birchas Hanehnin 2:7 regarding baked fruit filled pastry and 2:12 regarding deep fried; See Admur 168:7 and Admur 678:11 for full details of baked jelly filled Sufganiyot
 Seder Birchas Hanehnin 2:10; See Admur 168:14; Michaber 168:8
Other opinions: Some Poskim rule that a blessing is never to be said over Sufganyiot upon eating it during a meal, whether in middle or end, even for pleasure purposes. [Or Letziyon 2:12 p. 101 being that some Poskim rule that fried is similar to baking, as brings Michaber in 168:13 and that jelly filled dough is Hamotzi, as brings Michaber in 168:7 and Admur 168:14; Halichos Shlomo Chanukah p. 319 and Madanei Shlomo p. 45 being that they also satiate and certainly one’s intent is also on this] Other Poskim rule that while a blessing is never to be recited while eating it in middle of a meal, nevertheless it is to be recited when eaten at the end of the meal as dessert. [Yabia Omer 8:26-4; Chazon Ovadia Chanukah 19]
 According to Admur in the Seder ibid, both deep fried dough or baked Jelly filled dough is Mezonos according to all opinions being eaten for pleasure purposes. However, according to Admur 168:14, baked dough is Hamotzi according to some opinions even if it is Jelly filled, and hence a blessing would never be said, as brought in the other opinions in the previous footnote.
 Seder Birchas Hanehnin 2:12; Ketzos Hashulchan 48:9; P”M 318 M”Z 7
 Admur in Seder Netilas Yadayim 20; Admur 158:4-5; Michaber 158:4
 See Igros Moshe 4:74 regarding ketchup and the same would apply here; See Shabbos Kehalacha Vol. 1 p. 95 and p. 144, p. 147 that if the jam is not made of pure fruit then according to all it has the status of a liquid. If it is made from pure fruit, it is subject to the dispute mentioned below.
Other opinions: Some Poskim rule that one may heat it up on Shabbos on top of a hot pot that is on the Blech, being that the jelly is considered a solid. [Halichos Shlomo Chanukah 17:11; Chazon Ovadia Chanukah 19 in name of Rav SZ”A; See also Shabbos Kehalacha p. 147 that Rav SZ”A rules that ketchup has the status of Yaveish being that it derives from tomato paste, and something which was originally a solid remains a solid even when its turned into a flowing paste.]
 See “A Semicha Aid for the laws of Shabbos” Volume 1 in the sections of Chazarah and Bishul
 Shach Y.D. 329:4; Beis Lechem Yehuda 329:3; Pischeiy Teshuvah 329:1; Kaf Hachaim 242:27; See Michaber Y.D. 329:1 [exempt]; Rambam Bikurim 6:12 [exempt]; Beis Yosef 329; Pesachim 37b and Tosafus there [obligated if thick]; Rashba Toras Habayis 1 and Rosh Challah 2 and in name of Ramban [exempt if deep fried]; The Poskim ibid conclude to remove without blessing and suspect for both opinions
 Rivash 28; Peri Chadash 112:17; Beis Lechem Yehuda 112:14; Birkeiy Yosef 112:11; Kaf Hachaim 112:36 and 43; Sefer Hakashrus 19 footnote 14; The following Poskim rule that Mezonos products that cannot become Hamotzi upon setting a meal over them [such as deep fried products], do not retain the Pas Akum prohibition, but rather the Bishul Akum prohibition: Taz 112:6; Shach 112:18; Toras Chatas 75:12; Beis Yosef 12 in name of Rav Yechiel; Peri Chadash 112:17; Beis Lechem Yehuda 112:11; Rivash 28; Beis Lechem Yehuda 112:14; Kaf Hachaim 112:35-36; See Hakashrus 19:2; Sefer Mibei Midrasha 106
 See Rama 113:7
 Michaber 113:7; Birkeiy Yosef ibid; Kaf Hachiam 112:43; See Yechaveh Daas 5:53; Sefer Mibei Midrasha 106