Heat 1 Tsp oil in a frying pan and add mushrooms. Fry for 6-8 minutes over medium-high heat until the mushrooms are starting to caramelize and brown in the edges. Transfer it to a plate.
Add the remaining oil to the pan. Now add Onion, ginger, garlic, green chilli and saute for 4 -5 minutes until translucent.
Add tomato puree, spice powders, salt, 1/2 cup of water and cook for a few more minutes. Now add mushrooms, remaining 1/2 cup water, and simmer for about 3-4 minutes. Stir in lemon juice.
If you like it a little more saucy, splash some more water.
At this stage, sprinkle kasuri methi ( dried fenugreek leaves). This is an optional step.
Garnish with coriander leaves.Serve with basmati rice or naan bread.
Concentrated Tomato Puree is available in Tubes, easily available in supermarkets. You can use Tomato Puree or Paste in the recipe. White onion is my preference in this curry.Use Chestnut Mushrooms or White Button Mushrooms for this bhaji.