Marinate the fish slices with salt and black pepper powder.
Heat oil in a pan, shallow fry the fish slices.
In the same pan, add the remaining oil, when smoking hot, throw in the black peppercorn, cinnamon, crushed green cardamom and bay leaves. Saute for a minute or so, allow the spices to release their aroma.
Now add the onions, saute till light brown. Stir in the tomato puree and ginger paste, saute for 5-7 odd minutes till the raw smell of tomato is gone.
Throw in the potatoes, cauliflower florets, carrots and green peas, sprinkle in the salt and black pepper, continue to cook till the vegetables turn a light brown.
Add 2 cups of warm water, bring to a simmer. When the vegetables are almost tender, gently add the fried fish. Cook for a further 3-4 minutes over a high flame.
Reduce the flame, add the cabbage leaves and spinach. Pour in the milk, while stirring continuously and cook for 5-7 odd minutes.