Take refined flour in a bowl, add baking soda, salt, 2½ tbsps hot oil and sufficient water and knead into soft dough. Drizzle some oil over the dough, cover and set aside.
Put the drained split chana daal in a mixer jar and grind coarsely with very little water.
Add chilli powder, fennel powder, coriander powder, asafoetida, salt, garam masala powder and a little water, mix well and cook for 4-5 minutes. Remove from heat, add lemon juice, mix well and set aside to cool down to room temperature.
Heat sufficient oil in another kadai.
Divide both dough and stuffing mixture into equal portions. Stuff each dough portion with a portion of the stuffing, shape into balls ensuring that the stuffing is completely covered with the dough.
Slide in the kachoris into hot oil and deep-fry, on low heat, till golden brown. Drain on absorbent paper.
Arrange on a serving platter and serve hot.