Add all the spice mix ingredients, except dry mango powder and turmeric powder, into a grinder and grind into a powder. Transfer to a bowl, then add the dry mango powder and turmeric powder. Mix until well combined, then keep aside.
Wash and completely dry the chilies using thick kitchen towels. Then split the chilies lengthwise and remove the head.
Heat a skillet on medium heat and add the oil. Once hot, add the chilies and fry for 2 minutes, stirring continuously.
Add the salt and 3 tbsp of the prepared spice mix. Mix and saute for 2 minutes.
Reduce the heat and cover with a lid. Let cook for 5 minutes.
Let the mixture cool down and then transfer it to a clean and dry container.