In a hot skillet, dry roast cumin and coriander seeds. Transfer to a plate.

In the same skillet, heat 3/4 teaspoon oil. Roast garlic, shallots, chopper onion, dry red chillies until onions turn light brown. Remove from the heat and cool the mixture.

Transfer dry roasted cumin and coriander seeds, roasted onion mixture to a blender. Grind into a paste by adding required vegetable broth.

Heat oil in a deep wok. Add roughly crushed curry leaves. Add the diced potatoes and stir fry them until turns colour. Add in the ground paste. Cook for a minute.

Pour tomato puree. Mix. Cook for 2 minutes. Add turmeric. Add salt. Add vegetable broth. Cover the wok. Simmer and cook curry for 5 minutes until potatoes are cooked. Add the sliced mushrooms. Cover and cook until mushrooms are cooked. Adjust curry consistency as prefered.