First is a steel utensil add water and bring it to boil.
Then add salt, turmeric, vinegar and later add mushroom.
Let it boil for 2 mins.
Later drain and add mushroom in cold water.
Then drain and let them dry.

Then add salt and turmeric and let it dry for more 4 to 5 hrs.

In a pan add sauf, coriander seeds, Fenugreek seeds and carrom seeds and let them crackle. Now add mustard split seeds and pan fry for few minutes. let this cool down. Later crush it coarsely in a mixi.

In a bowl add thus powder and add onion seeds, kashmiri chilli powder,red chilli powder,black salt, dry mango powder, asphotida and lemon juice. Mix it well. (Adding 1/2 tsp sauf tastes good too)

In above mixture add mushroom and pour it in a clean and dry glass jar. Now heat oil and let it cool down. After that add it in glass jar. Tip- After oil reaches to bottom of the jar there should still be a inch above our mixture for pickle to last long.
Pickle will be ready in few days.