Peel the sweet potato, then cut into 2cm chunks. Thinly slice the spring onion. Thinly slice the garlic. Fill a medium saucepan three-quarters full with water and bring to the boil for the rice.
Step 2 — Cook prawns
Heat 2 tsp vegetable oil in a medium deep frypan over high heat. Cook the prawns, stirring, for 2-3 mins until just cooked through. Remove from the pan. Add the garlic, masala seasoning, 1½ tbs tomato paste* and 20g butter to the pan and cook, stirring, for 1 min or until fragrant.
Step 3 — Simmer curry
Add the sweet potato, half the tomatoes*, 60ml (¼ cup) coconut milk, ½ tsp sugar and 60ml (¼ cup) water to the tomato paste mixture. Bring to a simmer, then reduce the heat to low. Cover and cook, stirring occasionally, for 18 mins or until the sweet potato is tender. Stir in the prawns and cook for 30 secs or until warmed through. Remove the pan from the heat.
Step 4 — Cook rice
While the curry is simmering, cook the rice in the pan of boiling water for 12 mins or until tender. Drain.
Step 5 — Serve up
Taste the butter prawns, then season with salt and pepper. Divide the rice and butter prawns among bowls. Scatter over the spring onion, drizzle with 2 tbs coconut milk* and enjoy!
Step 6 — Make it yours
Like it crunchy? Scatter the butter prawns with chopped cashews or slivered almonds, if you have some on hand.