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 2 — Prep vegetables
While the rice is cooking, peel the pumpkin and cut into 2cm chunks. Halve the zucchini lengthwise and thinly slice. Thinly slice the spring onion.
Step 3 — Shred lime leaves
Separate the lime leaves, remove the central vein and finely shred (cut the lime leaves very finely to release the maximum flavour).
Step 4 — Start curry
Heat 2 tsp oil in a medium saucepan over medium heat. Cook curry paste, stirring, for 2-3 mins until slightly darkened. Add coconut milk and 250ml (1 cup) water and bring to a simmer. (It's important the curry doesn't boil or the coconut milk may separate.) Add the pumpkin and lime leaves, reduce heat to medium-low and cook, covered, for 10-12 mins until pumpkin is tender.
Step 5 — Finish curry
Meanwhile, cut the fish into 2cm chunks. Add the fish, zucchini and spring onion to the curry and simmer, uncovered, for 3-4 mins until the fish is just cooked. Stir in 3 tsp soy sauce, 1½ tsp white vinegar and ½ tsp sugar. Taste, then season with salt.
Step 6 — Get ready to serve
Add the sesame seeds to the rice and fluff the rice with a fork. Divide the rice and curry among bowls to serve.