Wash the spinach leaves well and let it rest in the colander for few minutes to drain. Then finely chop the leaves.
Pressure cook the toor dal with 1 cup water and a pinch of turmeric powder for 3 whistles. Mash the dal and set aside.
In a small pan, heat ½ tsp oil and add red chillies and urad dal. Fry till dal turns golden. Once it cools, grind with jeera and coconut to a smooth paste adding little water.
In a vessel add the spinach, turmeric powder and about 1 cup water. Cook the spinach uncovered over medium-low heat.
Once spinach is cooked, add ground coconut paste. Cook for 2-3 minutes. Then add mashed dal, salt and mix well. Add water if required. Bring to boil and simmer for 3-4 minutes.
In a small pan heat oil and add mustard seeds. When it crackles, add urad dal, red chillies and curry leaves. When dal turns golden, pour over the molagootal.
Notes
I have used palak keerai here, you can also use murungai keerai (drumstick leaves), arai keerai, mulai keerai or paruppu keerai.
After adding the dal, if its very thick then only add water and adjust the consistency.