Thinly slice the onion. Peel the sweet potatoes and cut into 2cm chunks. Coarsely chop the coriander leaves and finely chop the stems. Thinly slice the chicken.
Step 2 — 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. Fluff the rice with a fork.
Step 3 — Brown chicken
Meanwhile, heat 2 tsp vegetable oil in a medium deep frypan over medium-high heat. Cook the chicken, stirring, for 3-4 mins until browned. Remove from the pan. Heat 2 tsp vegetable oil in the pan over medium heat. Cook the onion and coriander stems, stirring, for 3-4 mins until softened.
Step 4 — Simmer curry
Add the chicken, sweet potato, curry powder, coconut milk and 125ml (½ cup) water to the onion mixture and stir to combine. Cover and bring to a simmer, then reduce the heat to medium and cook, covered, stirring occasionally, for 8 mins. Uncover and cook, stirring, for a further 5 mins or until the sweet potato is tender and the curry is slightly thickened.
Step 5 — Serve up
Stir 1½ tsp soy sauce into the curry. Taste, then season with salt and pepper. Remove the pan from the heat. Stir half the coriander leaves through the rice. Divide the coriander rice and curry among bowls, scatter over the remaining coriander and enjoy!
Step 6 — Make it spicy
If you like a kick of heat, scatter over a pinch of chilli flakes or thinly sliced fresh chilli just before serving.