Cut mushrooms in halves and wash them with the water, put these mushrooms in a strainer so that all water gets drained.
Take a pan and put butter in the pan and let the butter get melt at the medium-low flame, once the butter gets melt pour oil into the pan, as the oil gets a little warm add chopped onions and saute them till onions get soft. Now add mushrooms to the pan and saute them at least for 5-7 minutes.
Add garlic to a pan, saute it for 5 minutes, till the mushrooms are getting cooked, grind red chili and vinegar together and make a paste. Put this paste in mushrooms now add salt. Saute them for 10 minutes, add black pepper and basil, we have to saute mushrooms till they turn brown, it will take another 5-10 minutes approximately.
Your mushrooms are ready to serve. Eat them hot they will taste amazingly tasty.