- 25g/1oz butter
 - 115g/4oz leeks, trimmed, finely sliced (prepared weight)
 - 175g/6oz fresh white breadcrumbs
 - 2 tbsp chopped fresh parsley
 - 1 tbsp chopped fresh thyme
 - 150g/5oz Caerphilly cheese or Welsh Cheddar, finely grated
 - 2 free-range eggs, separated
 - 1 tsp English mustard
 - ½ tsp flaked sea salt
 - 5 tbsp sunflower oil
 - freshly ground black pepper
 - 2 tbsp sunflower oil
 - 2 medium red onions, finely sliced
 - 1 red chilli, finely chopped
 - 2 garlic cloves, crushed
 - 75g/2½oz light brown muscovado sugar
 - 5 tbsp white wine vinegar
 
- For the sausages, melt the butter in a large non-stick frying pan and fry the leek gently for 8-10minutes, or until very soft but not coloured.
 - Put 100g/3½oz of the breadcrumbs, the parsley, thyme and cheese in a large mixing bowl and mix until well combined. Beat the egg yolks with the mustard, salt and plenty of freshly ground black pepper in a separate bowl.
 - Remove the frying pan from the heat and tip the leeks into the bowl with the breadcrumbs. Add the egg yolks and mix together well with a large wooden spoon until well combined. Divide the leek mixture into eight portions and roll into sausage shapes. Place the sausages onto a tray lined with clingfilm.
 - Whisk the egg whites lightly in a bowl with a large metal whisk until just frothy. Sprinkle 40g/1½oz breadcrumbs over a large plate. Dip the sausages one at a time into the beaten egg and roll in the breadcrumbs until evenly coated, then place on the baking tray. Chill the sausages in the fridge for 30 minutes.
 - Meanwhile, for the relish, heat the oil in a large non-stick saucepan and fry the onions for 20 minutes, or until very soft and just beginning to colour. Add the chilli and garlic to the pan and cook for a further five minutes, stirring regularly.
 - Sprinkle with the sugar and pour over the vinegar. Bring to a simmer and cook for five further minutes, or until the liquid is well reduced and the relish becomes thick and glossy. Remove from the heat, set aside to cool for a few minutes then tip into a serving dish.
 - Heat the oil into a large non-stick frying pan and fry the sausages over a medium heat for 10-12 minutes, turning regularly until golden-brown and crisp. Serve the sausages with a good spoonful of chilli and onion relish and some thinly sliced runner beans.