Beef with Mustardy Lentils Recipe - River Cottage

Ingredients

• 200g Puy lentils
• 1 bay leaf
• 2 tbsp rapeseed or olive oil
• 1 onion, finely chopped
• 1 celery stalk, finely chopped
• 200g cold roast beef, cut into strips or torn into rough shreds
• 2 tbsp roughly chopped mint
• 2 good tsp English mustard
• 2 tsp cider vinegar
• 3 tbsp rapeseed or extra virgin olive oil
• Sea salt and freshly ground black pepper