Add 1 tbsp mustard oil in a non-stick pan, add fenugreek seeds, mustard seeds, cumin seeds, onion seeds and fennel seeds and saute till fragrant. Cool and grind to a powder.
Take yogurt in a bowl, add red chilli powder, turmeric powder, cardamom powder, salt, achaari masala, ground spice powder, ginger-garlic paste, ginger paste and roasted chana powder and mix well.
Trim off the ends and put the mushrooms into the bowl, mix well and set aside to marinate.
Cut red and green capsicum into square pieces equal or a little less in size to the mushrooms. Add this to the bowl, mix and let them marinate with the mushrooms.
Skew on one green capsicum piece, one red capsicum piece and a mushroom on each satay stick.
Heat 1 tbsp mustard oil in another non-stick pan, place the satay sticks in and shallow-fry, rotating the sticks so that they get cooked evenly on all sides.
Place the shashliks on a serving platter, garnish with mint sprigs and serve with a bowl of lachcha salad.