Take 2 tbsp of corn flour (makai ka atta) in a bowl and pour ½ cup of water in a bowl. Stir well to make a mixture and keep it aside.
Now, heat 1 tsp of butter in a pan on a medium flame. When the butter melts, put in 1 medium-sized onion (finely chopped) and sauté it well for a minute or so.
When the onions turn translucent, add 4 cloves of finely chopped garlic to it and sauté for another 20 seconds.
Now, add 8 to 10 pieces of chopped mushrooms in it and mix them nicely. Sauté them for about 2 minutes until they turn soft, get reduced, and release moisture.
After 2 minutes, add 3 cups of water and salt as needed to it. Bring it to a boil.
At this stage, pour the corn flour mixture that you made earlier to the soup. Mix it well and let it cook for 2 to 3 minutes.
When the soup thickens, add ½ tsp of black pepper powder (kali mirch) and a handful of freshly chopped coriander leaves to it.
Give it a nice final mix. Transfer it to a soup bowl.
Your tasty and healthy homemade mushroom soup is now ready. Garnish it with a pinch of black pepper powder and chopped coriander leaves. Serve hot.