Pressure cook potatoes for 4 minutes [i.e. after first whistle, reduce flame to minimum and cook for another 4 minutes.] Open the cooker once pressure subsides. Remove potatoes onto a dish and allow to cool for 15-20 minutes. Peel the potatoes.
Using a mortar pestle, crush the dried herbs along with salt to a coarse powder.
In a pan, (cast iron works best), heat oil. Add the chopped garlic and saute on low flame for a minute.
Transfer the herb-salt mixture, sesame seeds and sumac. Stir into the oil to combine well.
Add the peeled potatoes to the pan and toss to coat evenly with the seasoned oil.
Let this cook on a low flame for 15-20 minutes, giving it a shake 2-3 times in-between. We want the potatoes to be crusted with the herb-seed mixture as well as turn crispy and golden on the outside.
Serve hot as a starter or for a light meal along with a salad.