When you find the hog plum pieces soft, you can begin the process of pickling. So on the day of pickling, boil 1.5 cups of water adding 1/4 cup of salt. Let boil and reduce 1 cup. Let this salt water cool down.
Next in a pan add mustard, fenugreek and cumin seeds. In medium flame roast these spices with constant stirring.
Transfer these roasted spice and add red chillies to the same pan. Add 3 tsp of oil and roast them too. The chillies would puff up. Switch off the flame and let the roasted spices cool down.
Include all these roasted spices in a mixer jar, add asafoetida and powder them together.
Add the salt water prepared in step 1 little by little to the spice powder and grind to thick sauce consistency.
Finally transfer the hog plum pices in salt to a wide bowl. Include the spice sauce prepared in above step and give a nice mix. Adjust consistency by including salt water.
Palate tickling hog plum pickle is ready to serve with curd rice or matta rice ganji.