Soak the green mung beans overnight in water. Pressure cook the green mung dal with salt, turmeric powder and water, when its done; remove from the fire and settle down the pressure and keep it aside.
In stock pot, add the olive oil or butter and saute the chopped onions, carrots, celery, ginger, garlic along with all the spice powder. Saute for 5-10 mins.
Now add the chopped spinach and vegetable stock or water to the mixture. Saute for couple of mins. (Note : Don't over cook it)
Add the mung dal and simmer until everything gets well incorporated.Remove from the fire and let it cool.
Transfer the above to blender or to food processor and blend everything for couple of minutes or until smooth and creamy.
Return soup to the pot and bring to a simmer; Sprinkle the lemon juice and little red chilli flakes(optional), taste and season with salt and pepper. Serve with some earthy bread and Enjoy!