Indian
Boil the potatoes, cauliflower and peas in a covered pot with 150 ml of the water over medium-low heat for 12-15 minutes until very soft, then mash them roughly with any liquid left in the pot.
Melt 40 g of the butter in a wide pan or tawa over medium heat and fry 200 g of the onions for 5 minutes until soft, then add the ginger and garlic paste and fry for 1 minute.
Add the bell pepper and cook for 4 minutes, then add the tomatoes and cook for 6-8 minutes, mashing, until they break down completely.
Stir in the pav bhaji masala, chili powder and salt and cook for 2 minutes.
Add the mashed vegetables and the remaining 50 ml water and mash everything together with a potato masher; simmer for 8-10 minutes, stirring, until thick.
Finish the bhaji with the remaining 10 g butter and half the coriander.
Slit the pav horizontally, spread with the butter and toast on a hot griddle for 1-2 minutes per side; serve with the hot bhaji, raw onion, coriander and lemon wedges.