Dry Roast fenugreek seeds in a frying pan and dry grind them coarsely and keep it aside.
Heat oil in a pan, and add the mustard seeds, red chillies and hing . Keep aside to cool slightly.(I f you add hot oil to chilli powder it will burn it and discolour).
To the ground fenugreek add the chilli powder and salt and turmeric mix well. Add the warmed oil to the fenugreek mixture and mix well. Leave to cool.
Transfer the achar masala to sterelised jar and use as required. (Achar masala should be dry and crumbly extra oil is added as required when making the pickle).