Heat oil for deep frying in a deep heavy bottomed wok or skillet over medium heat. The oil should be about an inch deep in the pan. I use a tiny 8" diameter wok and about 3 cups of oil. When the oil is warm, add in a tablespoon of ghee for flavor.
Divide the dough into 25 equal portions. These portions will seem too tiny now but don't worry, the jamuns will grow quite a bit when fried and soaked. If you are stuffing the jamuns, flatten each dough portion and stuff a whole pistachio or raisin inside. Now roll each portion into a smooth, crack-free ball. (I have found that rolling them on a smooth plate using your palm makes very smooth jamuns).
When the oil has reached around 325F, drop in the rolled jamuns into the hot oil. Fry in batches so you don't over crowd the pan.
If you don't have a thermometer, see notes.
Fry the jamuns until they are nicely browned on all sides and keep turning them often to brown them evenly. The jamuns will double in size when fried.
Transfer fried jamuns directly into the warm sugar syrup mixture. When you have finished transferring all the jamuns into the sugar syrup, you can cover the pan and turn off the heat. Let them soak in the syrup for around 2 hours before serving. After 2 hours, the jamuns would have soaked most of the syrup and doubled in size again. Garnish with chopped pistachios and serve warm.
These gulab jamuns will keep well for up to one week in an airtight container in the refrigerator, if you haven't gobbled them all up by then! Just warm them up in the microwave or over the stove-top before serving.