Take out the upper layer of karelas, then put some salt on it and keep aside for 15 mins that will take out the sour taste of karela and then wash it with water properly so that the salt should be washed out.
Put a cut in karela in horizontal direction just to open it from one side and remove the hard seeds from inside then keep them aside n prepare the stuffing
Take out the extra water form the grated onions by squeezing them then mix the ginger paste, garlic paste,jeera, green chillies,garam masal,turmeric powder,spoon of mango pickle masala and salt in that mix that mixture properly
Stuff that mixture in the karela n tie then in circular direction
Heat the oil in non stick pan n put the karelas in that turn them time by time when one side is brown then turn the other side down.when all the sides are brown then take the pan from the gas n then take out the thread from the karelas n serve.