Coarsely chop the shallot and garlic. Halve the chilli, removing the seeds if less heat is desired. Peel and slice half the ginger*. Trim the end of the lemongrass stem, then cut off the dry woody section at the top. Peel off 2-3 tough outer layers, then coarsely chop half the pale, tender part of the stem*.
Step 2 — Make curry paste
Process the shallot, garlic, chilli, ginger, lemongrass, half the turmeric*, half the fish sauce*, 2 tsp sugar and 1 tbs oil in a small food processor until a coarse paste forms.
Step 3 — Cook rice
Rinse the rice until the water runs clear. Put in a small saucepan with 250ml (1 cup) water, cover and bring to a simmer over medium heat. Reduce the heat to low and cook for 12 mins or until tender and the water is absorbed. Turn off the heat and stand, covered, for at least 5 mins.
Step 4 — Cook curry sauce
Meanwhile, separate the lime leaves and remove the central vein. Finely shred half the leaves and set aside. Heat 2 tsp oil in a medium frypan over medium heat. Cook the curry paste for 1-2 mins until slightly reduced and fragrant. Scrunch the remaining lime leaves and add to the paste. Add the coconut milk and cook, stirring regularly, for 4-5 mins until slightly reduced.
Step 5 — Cook beans and prawns
While the curry sauce is cooking, trim the beans. Heat 2 tsp oil in a medium frypan over high heat. Cook the beans for 1 min or until slightly charred. Add the prawns and cook, stirring, for a further 2-3 mins until the prawns are just cooked through and the beans are tender.
Step 6 — Get ready to serve
Juice half the lime and cut the remaining lime into wedges. Stir the lime juice into the curry, then taste and season with salt and pepper. Fluff the rice with a fork. Divide the rice, prawns and beans among bowls. Spoon over the curry sauce and scatter with the shredded lime leaves. Serve with the lime wedges.