Wash the green chilies and then slit them from the center to separate the two parts but keep the stem intact to hold it together.(if the chilies are small in size then just prick them 2-3 times and can use them whole)
Heat oil in a pan and add fennel seeds and mustard seeds.
When mustard start crackling add asafoetida and turmeric powder.
Add the green chilies and salt and mix well.
Now cover the pan with a lida dn cook on low heat till the chilies become slightly soft.
Now add coriander powder, fennel powder and mango powder and mix it well.
Cover and cook for a minute so the spices get cooked .
Now switch off the flame and serve as a side dish or pickle with your food.
Stays well for 3-4 days at room temperature and for 10 days in refrigerator.