Marinate the Potatoes: In a bowl, mix potatoes with degi red chili powder, turmeric powder, salt, ghee, and ginger garlic paste. Set aside to marinate.
Prepare the Paste: Combine fried onions, cashew nuts, salt, turmeric powder, degi red chili powder, coriander powder, a little water, and tender coriander stems in a bowl. Grind into a smooth paste.
Fry the Potatoes: Heat oil in a kadai or handi, add marinated potatoes, and fry until half cooked. Transfer to an absorbent paper.
Prepare Changezi Aloo: In a cast iron tawa, heat remaining oil, add bay leaf, cinnamon, green cardamom, black peppercorns, cloves, and ginger garlic paste. Cook for a minute. Add tomato puree, curd, and cook well. Add the prepared paste, degi red chili powder, coriander powder, salt, and cook for 7-8 minutes. Add sugar, water to adjust consistency, and cook until it thickens. Add fried potatoes, mix well, and finish with crushed dry fenugreek leaves.
Garnish and Serve: Transfer to a serving dish, garnish with coriander sprig, and serve hot with tandoori roti or naan.