Heat a large saucepan, large enough to hold 1.5L of liquid.
Add the chopped chorizo, stir them around in the pan for a few minutes to release their juices. When chorizo has browned remove the pieces from the saucepan with a slotted spoon and set them aside.
Add the onion and garlic and sauté in the chorizo juices until softened, about 3 mins.
Add the curry powder and stir it in for a few seconds to release the flavours.
Add the potatoes, stir for a minute then add the stock and bring the mixture to the boil. Turn down to simmer for 30 – 35 minutes until the sweet potatoes are tender.
Blend in a food processor or blender and then return to the pan.
Season to taste, add back the pieces of chopped chorizo and serve.