Peel the potato skin off, cut into small cubes and soak in cold water until added. (This will help to keep the potato from turning dark and also helps to remove some of its starch)
Chop the onion and tomatoes. Crush the garlic and ginger and set aside.
Heat oil in a wok (frying pan), preparing this dish in an iron kadai will add extra flavor. Splutter mustard, split black gram, cumin seeds and curry leaves. Sprinkle some asafoetida powder.
Saute chopped onions along with crushed ginger & garlic until the turn light and soft. Add tomatoes and cook till lightly mushy.
Now drain all the water from the potatoes and add it to the onion tomato base. Bring the flame to low medium, cover and cook for 5 minutes. Do not add any water, just steam the potatoes over low flame until cooked through.
Once done, check if its cooked thoroughly, if not give it another few minutes.
Add turmeric powder, kuzhambu milagai thool (all purpose curry powder) along with salt. Saute well to cook the masala powder.
Again, reduce flame to low, cover and cook it for 2 to 3 minutes.
when done, slow roast for few minutes and garnish with curry and coriander leaves.
Turn it off! Serve as a side for any rice dish!
Notes
**** Kuzhambu Milagai Thool - its an all purpose curry powder used for stir fries / varuval recipes. Spice blend that includes lentils, dry red chilies, coriander, black pepper, cumin and fenugreek seeds. You may replace it with just 1 tsp of red chili powder and 2 tsp of coriander powder OR use sambar powder. Depending on the spice level and concentration of the flavors use 1 to 2 tbsp of sambar powder to replace kuzhambu milagi thool.