Soak yellow moong dal and chana dal separately for at least 4 hours.
After 4 to 5 hours, drain off the water and grind both the lentils into a fine paste.
Do not keep the batter too thick. Preferably have fallen ribbon-like consistency.
If possible, keep the batter for half an hour in the refrigerator. In winters you can leave it outside the refrigerator also. This results in slight fermentation of the batter which in turn produces good pakoras.
Whip the batter for 15 to 20 minutes manually or 7-8 minutes by an electric beater.
Once whipped fully, the batter becomes light and fluffy. Also, check for it. Take a small bowl filled with water. Put little batter in it. If it floats then the batter is ready for frying. If settles down or disperse in water then whip for some more time. One more test is that colour of the batter changes from yellow to almost white when properly whipped.
You may add little chopped coriander leaves in the batter.
Once the batter is ready, keep the frying pan on flame and heat oil for frying.
When the oil is sufficiently hot, reduce heat and put dollops of batter in it for frying. Put 6-7 dollops at a time depending on the size of the pan.
Once dropped in the oil, increase the flame and fry these Pakoras till golden brown. While frying, keep tossing the Pakoras.
Once fried, take them out. Similarly, fry other Pakoras.
Now either use it immediately or store in an airtight container in the refrigerator for a day or two.