1 Granny Smith apple
300²µ/10½´Ç³ú celeriac
2 green chillies
½ bunch coriander
1 garlic clove, crushed
8 mint leaves
½ bunch flat leaf parsley
salt and freshly ground pepper
1 tsp chopped rosemary
1 tsp Dijon mustard
2 tbsp dark brown sugar
1 tsp mustard powder
5 tbsp olive oil
2 tbsp cold pressed rapeseed oil
1 tbsp sherry vinegar
1 tsp smoked paprika
2 tbsp Greek-style yoghurt
500g/1lb 2oz pork loin cut into 2.5cm/1in-thick fillets
4 brioche buns halved