Pickled walnut ketchup

• 1 onion, thinly sliced
• 1 tsp sunflower oil
• 1 Bramley apple, peeled, cored and chopp

Sweat down the onion in the oil until soft. Add the apple, then mix in the sugar and a pinch of salt. Finally, add the drained pickled walnuts and cook for about 10 minutes until the apples are very soft.

Blitz until smooth, then taste and adjust the seasoning if needed.