BBC Food - Recipes - Herb-crusted rack of lamb with aubergine purée

Ingredients

• 1kg/2lb 4oz lamb bones, chopped (ask your butcher for these)
• 2 bay leaves
• 1 sprig fresh rosemary
• 1 litre/1¾ pints ready-made chicken stock
• 1 large aubergine
• 2 tbsp olive oil
• 1 tsp chopped fresh dill
• 1 tsp chopped fresh mint leaves
• 1 tbsp Greek-style yoghurt
• ½ lemon , zest and juice
• salt and freshly ground black pepper
• ½ tsp cardamom pods
• vegetable oil , for frying
• 1 x 6-bone rack of lamb
• 2 thick slices sourdough bread
• small bunch fresh mint
• 2 tbsp English mustard , plus extra for brushing
• 800ml/1 pint 8fl oz reduced lamb stock (from above)
• 1 tbsp red wine vinegar
• 1 tbsp soft dark brown sugar
• small handful chopped fresh mint leaves