Open the coconut milk without shaking and spoon the thick cream off the top into a hot pan.

Fry the curry paste in that cream for 3-4 minutes until the oil visibly separates and the mixture darkens. This step is the whole difference.

Add the grated ginger, then the diced sweet potato and the rest of the coconut milk. Simmer 12 minutes.

Add the peppers and green beans and cook 6 minutes more — they should keep some bite.

Stir the spinach through until wilted.

Finish off the heat with lime juice and salt. Curry needs acid at the end or it tastes flat and heavy.