Sauté the aromatics (optional but recommended): Heat a splash of oil in a frying pan over a medium heat. Add the diced onions and cook for 5 minutes until they turn translucent and smell sweet. Stir in the garlic and ginger and cook for one more minute until they release their fragrance. This step deepens the flavour, but you can skip it and throw everything straight into the slow cooker if you’re truly pressed for time.

Bloom the spices: Add the curry powder, cumin, coriander, and turmeric to the pan with the onions. Stir constantly for 30 seconds until the spices become fragrant and the mixture looks a shade darker. This unlocks their essential oils.

Layer the slow cooker: Tip the spiced onion mixture into the slow cooker. Add the sweet potato chunks, then the chicken pieces on top. The chicken will release juices that help cook the sweet potatoes evenly.

Add the liquid base: Pour over the chopped tomatoes, chicken stock, and tomato purée. Give everything a gentle stir so the ingredients are just combined. The sauce will look thin now, but it will thicken as the sweet potatoes soften.

Season and cook: Sprinkle over the salt and pepper. Place the lid on and cook on low for 6 hours, or on high for 3 hours. The chicken should be tender enough to pull apart with a fork, and the sweet potatoes should be soft but still holding their shape.

Check the consistency: After cooking, the sauce will have thickened naturally. If it looks too thin for your liking, remove the lid and cook on high for a further 20-30 minutes to reduce it. You’ll see the sauce clinging to the back of a spoon when it’s ready.

Finish and serve: Taste the curry and adjust the salt or add a pinch of chilli flakes if you like heat. Stir through the fresh coriander just before serving. The final dish should have a deep golden colour and a rich, aromatic smell.