Wash the urad lentils 2-3 times. Soak for 6 hours.
Once soaked, drain the water completely.
Add lentils to a grinder/blender along with ginger, green chilies, cumin, fennel, nigella, red chili powder and hing. Grind the dal to a coarse paste. If needed, add as little water as possible (1-2 tbsp).
In a large bowl, add flour, ground lentils and salt. Mix everything with hands. Add oil and mix as well.
Start adding little water and knead into a firm stiff dough. I used about ⅓ cup water. Add water slowly while kneading. Knead the dough for about 8-10 minutes to make as smooth as possible. Cover the dough with a damp cloth and rest for 20 minutes.
Pinch equal portions form the dough depending on how large/small or thin/thick you want to make pooris. Roll the portions into smooth balls
In a kadai/wide pot, set oil on a medium high stove to heat up.
Without using any dry flour, roll the balls into to a 3-4 inch circle. You can use little bit of oil while rolling if needed.
Slide the rolled poori into the hot oil and deep fry till slightly browned from both the sides. Gently press the pooris while frying so that they puff up. Drain them on a plate lined with paper towel. Repeat till all pooris are fried up. Serve.