I boiled the potatoes whole, covered with water in a pressure cooker. 1 whistle and let the pressure release naturally. For instant pot, use 10-12 minutes and natural pressure release. Microwave works too. Or boil peeled and cubed potatoes in an open pot of water until tender. You don’t want them to get mushy
If you cannot find amchur powder, you can use lime/lemon juice, about from ½ a lime. Just to add some tang.
To bake the stuffed bell peppers, preheat the oven to 350 degrees F/ 175 degrees C. Spray/brush the peppers with oil, set in a greased baking sheet and bake for 25-30 minutes. You might want to give a quick broil at the end to get some crust on the potatoes.