Roast moong dal in a saucepan without oil for 5-7 minutes. When the colour is slightly changed add 2 cups of water and cook till its done. Let it cool for sometime. Mash the dal using a blender/food processor (you can also mash it using the back of a wooden spoon, since I like the dal to be mashed well I used food processor).
Heat oil in a pan & splutter jeera. Add crushed garlic & saute for a few minutes. Add chopped onion and green chili . Saute till the onion becomes soft. Add turmeric powder, chopped tomatoes & salt. When tomato becomes soft add mashed dal and 3/4 - 1 cup of water. Mix well & add palak. Cook till the palak leaves are done.
At this stage you can add either 3/4 cup of coconut milk or water. Sprinkle the garam masala and cook for 5 more minutes. Adjust the gravy as per your requirements.
Notes
Though the original recipe uses coconut milk, I didnt add it. Anyways for a creamier and richer version you can add coconut milk.You can also cook the dal using pressure cooker. After roasting the dal in pressure cooker, add 2.5-3 cups of water. Cook on high flame for 5-6 whistles. Keep it closed for 15 mins. Open the cooker and follow the rest of the recipe.