Take 2 medium-sized potatoes, wash them, and remove the skin. Then cut the potatoes into small cubes (refer to the video).
Heat oil in a pan, add the potato pieces, and fry until they are crispy and golden brown. Remove them onto a plate.
In the same hot oil, fry 6 tbsp peanuts, 6–7 green chilies, and 7–8 garlic cloves until slightly golden brown. Remove them onto a plate and let them cool.
Now add the fried peanuts, green chilies, and garlic cloves to a mixer jar. Coarsely grind them using pulse mode and keep aside.
In a bowl, add the fried potatoes and roughly mash them with your hand. Then add 1 cup chopped onion, the crushed peanut–green chili–garlic mixture, 1 tsp amchur powder, and salt. Mix well.
Heat 2 tbsp oil in a tadka pan. Add 1 tsp mustard seeds and sauté. Switch off the gas and add 1 tsp Kashmiri red chili powder and ¼ tsp turmeric powder. Mix well and pour the tempering over the chutney.
Add some coriander leaves and 1 tsp lemon juice. Mix well.
Batata thecha chutney is ready. Serve with roti, paratha, or khichdi.