3 hr 30
Put all the ingredients except the vinegar in the slow cooker and season with pepper. Add extra stock to cover the lentils, if necessary.
Cover the cooker with the lid and cook on HIGH for 3 hours until the lentils and sweet potato are tender.
Remove the pepper pieces and discard. Stir well and season with salt and a little more pepper, if you like. Stir in the vinegar, sprinkle