Preparation time: 45 mins
Heat the rapeseed oil in a thick bottomed saucepan and fry the onion and garlic until just softened with no colour.
Add the apple and chilli and fry for a further minute. Stir in the sugar, soy sauce, chicken stock, vinegar and tomato ketchup.
Simmer gently until the apples are softened. Transfer to a blender and blitz until smooth. Pass through a fine strainer. The sauce can be served warm or at room temperature and can be stored in the fridge for up to 4 days.