Toast the cashew nuts in a dry wok until they start to brown and fill your kitchen with a wonderful nutty aroma. Set to one side.
Add the vegetable oil to the wok and heat on a medium flame for a few minutes. Pop in a mustard seed or two. If it fizzles and pops then the oil is hot enough.
Add the mustard seeds to the oil and let them crackle and pop for a few seconds.
Add the green chillies closely followed by the potatoes. Turn the heat down a little and cover to stop it all spitting at you.
Lift the lid and add the spices and salt then pour over the tin of coconut milk.
Fill the tin with water and pour that in, stir and then cover again.
Leave that to cook for 5 minutes and then add the sweetcorn and toasted cashews.
Leave that for a further 5 minutes and the potatoes should be cooked, the sweetcorn nicely steamed with a little bite and the cashews softened.
Garnish with the fresh coriander and then serve as is with crusty bread. Or serve on top of a bed of fluffy rice, quinoa or couscous. Up to you.