Heat the oil in a deep frying pan, and add the onion, apple and garlic. Cook over a low heat for 5-10 minutes, until everything is very soft. Add the curry powder and flour, and mix well. Then pour over the stock and add plenty of black pepper.

Bring to a gentle simmer, and cook for around 10 minutes, stirring every couple of minutes, until the mixture is thick and the vegetables have cooked right down.

Your sauce will probably be quite chunky, so if you’d prefer a smoother sauce, just give it a quick blitz with an immersion blender. This will thicken it up a bit too. I half-blended mine, so it was quite thick, but there was still some texture.

Serve on fat chips.