This is a two-pot stovetop affair. Veg and gravy are cooked separately and then combined.
Tempering – creating a flavoured oil for cooking in
Put some oil into pot and wait till it gets hot, then throw in the tempering spices and let them sizzle for about 5-10 seconds, then lash in the vegetables, carrots first, then potatoes, roll them around and get them covered in the flavoured oil, follow up a minute later with the rest of the veg items.
Turmeric, salt and water goes in next, and stir it up, cover it and let it cook, keep an eye on it so that veg doesn’t stick. Goal here is to have cooked veg in this pot, into which the gravy gets added.
In a smaller pot, it’s gravy.
You are going to put this through a blender to smooth it out, so the onions don’t need to be chopped super tiny. If you are not blending, then chop them super tiny!
Put some oil into pot and wait till it gets hot, then throw in the tempering spices and let them sizzle for about 5-10 seconds, then in with the onions, garlic, ginger and cook till onions are browning up. Add the can o tomatoes, purée and all the spices, stir it up and cook on low for another 10 min. Blend it all for a smooth gravy, then stir on the cashew nut paste.
Mix the gravy into the pot of veg and bate it inta ya.
Note that there is no shame in drinking the gravy out of a mug on your own in in the kitchen.