Heat oil and season with cumin seeds. Saute onion, tomato, green chilli, ginger garlic and cashews for 10 minutes over medium flame or until the onion turns soft.
Once done,let cool completely and make a paste without adding any water. Keep this aside.
To steam veggies
Bring 2 cups of water to a rolling boil, add in chopped carrots, green peas and potato along with pinch of sugar and salt. Cover and cook for 5 minutes over medium flame and switch off. Keep this ready along with the stock.
To make the gravy
Heat oil in a pan and season it with cumin seeds and start sauteing finely chopped onion until it turns crisp and glossy.
Add in the gravy base paste that was prepared ahead and saute along with the onions.
Now add turmeric powder, kashmirc hilli powder, coriander powder, garam masala powder, sugar & salt. Saute for 5 minutes until the spice mix blends with the onion paste.
Once the masala cooks, the oil will ooze out of it and that's when you add the tomato puree and cook along.
Now at this stage add in mushroom, capsicum & cauliflower. Cover and steam it along with the gravy for 5 minutes over low flame. (Caution: Over cooking cauliflower can make it mushy and that will change the look & taste of gravy)
When done add the steamed veggies along with the stock.
While that is simmering add the thick coconut milk followed by heavy cream.
Simmer until the gravy thickens and turns glossy.
Switch off, top it with crushed kasuri methi and chopped coriander leaves.