I prefer to soaking the dal overnight, as it reduces the cooking time well. If in hurry the dal can also be soaked in warm water for an hour or two and pressure cooked to get a soft texture.
Cook it on the stove top or pressure cooker until done. Or microwave cook it for 8-10 minutes @ MW high. Dal shouldn't turn mushy.
Peel the Potato, cut into cubes and cook them in Microwave for 8 minutes or on the stove-top until done. These too shouldn't turn mushy.
When i cook potatoes on the stove-top, i switch-off the stove once the water has boiled for 5 minutes. Cover and keep for another 5 minutes. Drain and set aside. They will be AL Dante.
Heat oil in a Kadai/Non-Stick pan, throw in the cumin seeds, when it crackles, add onions, slited green chili, garlic, ginger and saute until onions turn translucent
Add tomatoes, Red Chili powder, coriander powder, turmeric powder, garam masala Powder and ½ cup of water. Let the tomatoes cook and release oil
Add cooked potatoes and cooked moong, salt and another ½ Cup of water and milk. If skipping milk, add more water
Cover and cook for 8-10 minutes in a simmer flame. Take it off the stove, Garnish with fresh coriander leaves and serve with roti's/rice