To make the spice paste, trim the lemongrass, discarding the root end and any stiff outer leaves. Put the lemongrass, lime leaves, peeled garlic, half the coriander and tomatoes and chillies, seeded if you like a cooler curry, into a food processor. Peel and roughly chop the ginger then add to the processor. Blend to a rough paste, scraping it down occasionally with a rubber spatula.

Pour a thin layer of vegetable oil into a heavy-based saucepan, add the spice paste and leave to cook over a moderate heat for a couple of minutes, stirring occasionally until the paste darkens very slightly in colour. Add the pumpkin and broad beans and stir to coat in the paste. Add the coconut milk, fish sauce, sesame oil and light soy sauce, stir and leave to simmer gently for 15-20 minutes. Add lime juice and check seasoning. If more salt is needed, add a few drops of fish sauce.

To serve, spoon over steamed rice and scatter with remaining coriander, then top with fried shallots and Thai basil.

Tip A great alternative to rice is steamed cous cous.