Slow cooker lentil soup
This is made possible by BBC Foods! Ingredients 1 tbsp olive or vegetable oil 2 leeks, trimmed, cut in half vertically and sliced into 2cm/¾in strips 3 carrots, peeled and finely diced 2 celery stalks, finely diced 400g/14oz baby potatoes, quartered 150g/5½oz dried red lentils 400g tin chopped tomatoes 1.25 litres/2¼ pints vegetable stock 6 thyme sprigs, leaves picked 2 bay leaves salt and freshly ground black…