Spiced vegetable mash with buttered buns (Pav bhaji)

1. Peel and dice the potatoes and cook with the cauliflower florets and peas in the water for 15 minutes until tender; don't drain. Roughly mash with a potato masher.

2. In a wide frying pan (in Mumbai it's made on a large, flat tawa) melt half the butter and fry the finely chopped onions for 6 minutes until soft, then add the ginger, garlic and finely diced pepper and fry for another 4 minutes.

3. Add the diced tomatoes, chilli powder and pav bhaji masala and cook for 6-8 minutes, pressing the tomatoes to a pulp with the back of a spoon.

4. Add the vegetable mash with its cooking water, season with salt and keep mashing in the pan until smooth and thick. Cook for 10 minutes, stirring, then stir in the remaining butter and half the coriander.

5. Halve the buns horizontally. Melt a little butter in the pan, sprinkle with a pinch of pav bhaji masala and toast the buns cut side down for 1 minute until crisp.

6. Serve the bhaji with a knob of butter on top, the toasted buns, finely chopped raw onion, coriander and lemon wedges.

Tip: Mumbai's best-known street food, invented in the 1850s as a quick lunch for textile mill workers. Pav bhaji masala is sold as a ready-made blend; don't skimp on the butter: that's what gives it its true Mumbai flavour.