Melt the butter in a pan (if you are health conscious, use olive oil instead) and add the chopped onions and saute them till translucent (Do not let them turn brown).

Add the chopped mushrooms, coriander and garlic to the onions and saute till they're soft.

Take 3/4 th of the mixture and grind it well in a mixer to make a paste. Add water as and when required, while grinding.

Add the paste to the rest of the unused sauted mushroom mix.

Add the black pepper or use white pepper powder if you prefer less spice and leave on low flame for 2-3 minutes, until it boils.

Turn off the flame and serve hot with garlic bread.