300g (10½ oz) red split lentils, picked over for any stones, washed and drained very well

1 dried lime, black or regular, pierced a couple times with a sharp knife

2 large plum tomatoes (250g/9 oz)

1 chicken or veggie stock (bouillon) cube

½ red onion, finely chopped

250g (9 oz) floury potatoes such as Maris Piper (about 1–2), peeled and cut into 3–4cm (about 1½ in) chunks

1 tsp cumin seeds, toasted and very finely crushed using a pestle and mortar

2 tsp coriander seeds, toasted and very finely crushed using a pestle and mortar

¾ tsp garam masala

1 tsp ground turmeric 3 tbsp lime juice

20g (¾ oz) coriander (cilantro) leaves, roughly chopped

Fine sea salt and freshly ground black pepper

For the onion topping:

150ml (5 fl oz) olive oil

2 onions, finely chopped

30g (1 oz) fresh ginger, peeled and finely grated

5 garlic cloves, finely grated

1 green chilli, finely chopped, seeds and all

4 dried mild red chillies

20 fresh curry leaves (from 2 stems)

1½ tsp black mustard seeds

1 tsp cumin seeds

Add the lentils, dried lime and 1.6 litres (54fl oz) of water to a large, lidded saucepan over a medium-high heat. Bring to the boil, skimming any scum from the surface, and cook for 15 minutes with the lid off, or until the lentils are quite soft.

Meanwhile, use a small, sharp knife to remove the core from the tomatoes and score the opposite end with an ‘X’. Place in a medium heatproof bowl and pour over enough boiling water to cover. Leave for just 2–3 minutes, then drain off the water and peel and discard the skins. Roughly chop the tomatoes into 2cm (¾ in) pieces.

When the lentils are ready, add the tomatoes, stock cube, red onion, potatoes, spices, 1¼ teaspoons of salt and a generous grind of pepper. Cover with the lid, turn down the heat to medium and cook for 15–18 minutes, stirring a couple of times throughout, or until the potatoes are nice and soft. Take off the heat and stir in the lime juice and fresh coriander.

Towards the last 10 minutes of cooking, make the topping by heating the oil in a medium sauté pan over a medium- high heat. Add the onions and fry for 10–12 minutes, stirring occasionally, until nicely golden. Stir in the ginger, garlic and green chilli and cook for 2 minutes more, stirring often, until fragrant. Lastly add the dried chillies, curry leaves, mustard

and cumin seeds and fry for 1½ minutes more, stirring often, or until the leaves start to turn shiny and translucent and the onions are deeply brown. Immediately pour this into the finished dal, stirring to incorporate.

At this point, feel free to add a splash more water if you prefer a thinner dal. Serve warm.