Place half cup of water in a pan (pressure cooker) and add the potatoes, carrots, peas and head of cauliflower.
Cover and cook all the vegetables until soft.
Meanwhile heat up the oil in a large pan or wok.
When the oil becomes hot, add the cumin and mustard and the asafetida when the cumin/mustard start spluttering.
Immediately add the onion and sauté until light brown.
Next add the garlic and the masala mix. Keep stirring and fry for a couple of minutes.
Add the tomatoes, salt and the puree. Mix thoroughly.
Roughly mash up the cooked vegetables, add to the pan and mix.
Taste and adjust salt and masala as per taste. The resulting Bhaji should be slightly liquidy. So you might need to add water, but do this in stages for if the Bhaji becomes too runny, then it will also lose the taste.
Transfer to a big bowl and garnish with the chopped coriander.
Just before serving, toast the buttered halves of buns under a grill (traditionally they are roasted on a frying pan with plenty of butter).
Serve two halves of bun with a good helping of the vegetables (Bhaji).
Squeeze some lemon juice as per taste.
Another tradition of our household is to eat the Pav Bhaji topped with slices of flavoursome hard cheese. This can also be served, topped with fresh finely chopped onions. This is a very simple and quick meal to make after a busy day at work. The spicy Bhaji tastes great with the crispy Pav.