Soak the urad dal overnight. Drain the water, make a smooth paste with very little water.
Add the fennel seeds, freshly ground fennel powder, hing and baking powder to the urad dal paste.
Whip the dal paste well to mix thoroughly till light and fluffy. The consistency is key to the success of the roshboras. If the paste is too sticky, feel free to splash a little water, mix well.
Heat oil in a deep bottomed pan, take small portions of the dal paste, form small dough balls and release gently into the hot oil. Fry till golden. Keep aside on a kitchen absorbent towel.
Heat the water and jaggery in a pot for about 12-15 minutes till you get a nice golden syrup. Feel free to throw in more jaggery if you want it sweeter.
Soak the fried boras in the hot jaggery syrup for at least 3-4 hours. Remove from syrup and serve.