Pick up the tender shoots and leaves from the long, fibrous methi stems. This step takes time. Then, soak and wash the leaves under running water 2-3 times to remove all the dirt. On a clean kitchen towel, spread the washed methi to completely air dry for atleast 30 to 45 minutes. If you are in a hurry, use paper towel to press down and absorb all the moisture. Ensure that the leaves are totally dry once you are ready to cook else the sabzi will come out watery.Once the methi leaves are dry, chop them.
In an iron karahi or heavy pan, heat up the mustard oil on medium until the raw smell goes away. Once hot, temper the oil with methi dana and cumin seeds. Wait till they crackle. Turn the heat to low and immediately add the chopped garlic hing and dried chillies. Wait till the garlicchanges color to light brown and the dried chillies swell, about 10-12 seconds in hot oil. Take utmost care that the garlic does not burn. You can even put off the stove for few minutes.
Reduce the stove to low and next add the potato cubes and sprinkle the turmeric and chili powder. Stir around and get the potatoes started in oil. Cook the potatoes for about 2-3 minutes.
Add the chopped methi leaves. Stir to combine. The methi leaves will wilt down in 1-2 minutes and you will see the water of the methi separating. Let cook uncovered for 3-4 minutes on medium low heat and then add the dill. Add the salt next. Stir so that everything is combined. Cover for a 3-4 minutes and cook until the potatoes are done.
Once done, methi will be a darker shade of green and will stick to potatoes. Put off the heat, sprinkle amchoor, mix gently (so that potatoes dont break) and let sit for at least 1-2 hours before serving (this is important).
Warm up and serve.