Wash and wipe all chillies. Let it dry for 10 minutes.
First cut stalk of one chilly then chilly lengthwise in middle and take out maximum seeds. You can cut chilly upper part with stalk and deseed it. Choose any process u like. After cutting process let it dry for 45 minutes under fan.
Heat a heavy bottom pan on medium heat. Dry roast fenugreek, fennel, coriander seeds one by one ; cool down. Now put mustard seeds in pan heat just for few seconds then take out from pan.
Now heat oil till smoke comes out then add asafoidea and heat for a minute. Switch off the gas flame and cool down naturally. You can do this process before processing chillies also.
Make fine powder of all spices ; cool down.
Take a large bowl. Put all dry spices, powdered spices, turmeric powder, kashmiri chilly powder, chilli seeds, black salt, 100gms dry mango powder, salt, 1/4 cup oil then mix well. Now adjust sourness and salt of masala mix as per your preference.
Take a chill in hand then press lower part of chilli its middle space will open properly. Fill chilly with the help of a spoon. Press masala mix then fill little more spices mix. Keep it in a dry plate. Repeat this process for rest chillies.
Take a big clean and dry glass jar. Place all stuffed chillies in jar in a proper way. Sprinkle little spices mix in middle if some quantity is left.
Now pour rest of oil in the jar and cover up all pieces. Tie a clean muslin cloth on neck of jar.
Keep this jar in sunlight for 15 days. After 14 hot days leave it like this for one day ; when glass jar will be cool down then take out muslin cloth and put the lid.
Tasty, mouth watering pickle is ready to enjoy. Serve it with any meal specially we love to eat with poori, paratha, chapati and steamed rice. It increases taste of any meal.