Grind together mint leaves, coriander leaves, shallot, salt and 1 tsp mango powder. Don't make it too fine and leave it bit coarse.
Make the Pakoras
Slice the paneer into about two inches squares and about 1/4 inch high.
Add the mint filling between the two slices of paneer (like you make a sandwich) and set them aside.
Mix together all the other ingredients of the besan batter. Make sure that the mixture is smooth and there are no besan solids. Mixture shouldn't be too runny or thick. Add or remove water if needed
Set the oil to medium high heat in a wok.
To test whether the oil is hot enough, take 1/4 tsp of the besan mix and add it to the oil. If the besan mixture rises to the surface quickly, then the oil is ready to start frying. However, if the oil is producing smoke, it's too hot.
Dip the paneer slice (sandwiches) in to the besan batter and make sure it's covered with the batter on all sides
I use smoked mustard oil for frying. To smoke a mustard oil, heat up the oil until it starts to produce smoke. Turn off the heat and let the oil cool. Now, you can use this oil for frying. However, you can use any oil which is suitable for frying.