Lentil Soup

1 brown onion 1 carrot a sprig of thyme 1 cup lentils a little olive oil 1 litre vegetable stock 4 Tbsp chopped parsley 400g tin peeled tomatoes freshly ground black pepper a small glass sherry (optional) 2 Tbsp grated cheese (optional) Peel and dice onion and carrot.  Wash and chop thyme and wash lentils. [...]