Fill your kettle and boil it. Peel and finely chop the onion. Peel and finely grate the garlic and ginger. Halve the chilli, if you’re using it, (you can flick out the seeds and pith for less heat) and finely chop the chilli.

Trim and chop the courgettes into 1cm-thick slices. Scrub and trim the carrots (no need to peel) and slice them to match. Halve or quarter any large potatoes, so they’re all roughly the same size.

Warm a large, heavy-based pan on a medium heat for 2 mins. When warm, pour in 2 tbsp oil and tip in 2 tsp cumin seeds, 1 tbsp black mustard seeds and the curry leaves. Add a pinch of salt, then stir and fry for 2 mins till the seeds start popping. Take care not to let them burn.

Turn the heat down to low and add the onion to the pan. Fry with the seeds for 5 mins, stirring often, till just softened.

After 5 mins, add the garlic, ginger and courgettes to the pan. Add 1 tbsp turmeric and the chilli, if using it, and stir. Turn the heat back up to medium and fry for 2 mins.

Add the carrots and potatoes to the pan. Pour in the coconut milk and 500ml boiling water. Add a good pinch of salt and pepper.

Bring the curry up to a bubble, then turn the heat to low. Cover the pan and simmer for 10 mins till the potatoes are nearly tender. While the curry is cooking, chop the flat beans into thin slices, almost shredding them.

When the curry has cooked for 10 mins, add the shredded flat beans to the pan. Stir and cook for 2-3 mins till the beans are al dente (tender with a slight bite).

Taste the curry and add more salt or pepper if needed. Spoon the curry into warm bowls and top with the coconut flakes. Serve with a wedge of lime to squeeze over.