Clean spinach, chop roughly. Peel off the skin of beetroot, chop roughly. Finely chop onion. Slit tomato into two.
In a small pressure cooker, heat 1 tbsp oil, add onion to it with a pinch of salt. Fry until onion turn soft. Add cumin powder, give a quick stir.
Place tomato, chopped beetroot. Pour 2 cup water and pressure cook for 3 whistles or until beetroot is cooked.
Open once the pressure is released. Using immersion blender, grind smoothly.
Again start heating the soup, add chopped spinach to it. Simmer for 5 minutes or until spinach is cooked soft. Switch off once done.
Meanwhile, heat a heavy bottomed pan with remaining oil, add cooked chickpeas, sambar powder and required salt. Mix well.
In low flame, cook so that the chickpeas turn crispy (roughly 10 mins). Stir occasionally for even cooking.
Top the soup with the crispy chickpeas while serving.