Step 1: Splutter mustard seeds in little oil, saute garlic, jeera, chilliesand turmeric powder.
Step 2: Add the onions, saute until golden brown, then the tomatoes if adding.
Step 3: Boil moong dal separately and add to this mixture or you can soak the dal for an hour and add it to the pan with water, let it cook.
Step 4: Now add the spinach and salt, close with a lid and let it cook. You may let it become thick if using as a side dish or leave the dal a bit liquidy if eating with rice.