Make the tangy paste. In a blender jar, combine the raw mango pieces, ginger, garlic, 2 green chillies, black salt, 1 teaspoon of cumin seeds, coriander leaves, coriander powder, regular salt, and lemon juice. Blend into a coarse paste. Do not use any water!
Sauté the onions. Heat a pan over medium heat and add a little oil. Add 1 teaspoon of cumin seeds and hing. Drop in the chopped onions and lightly roast them just until they soften. Remove the onions from the pan and set them aside.
Roast the chillies. In the same pan, add a little more oil. Add your 25-30 slit green chillies, turmeric powder, and a tiny pinch of salt. Sauté until the chillies develop nice blistered, dark spots.
Mix it all together. Lower the heat and add your blended raw mango paste over the blistered chillies. Next, bring the roasted onions back into the pan.
Final toss. Sauté everything together on medium heat for 2 to 3 minutes. Make sure not to overcook the onions; they should retain a slight crunch.
Cool and store. Your delicious Raw Mango Onion Mirchi Recipe is ready! Let it cool completely before storing it in an airtight container.