Colourful root vegetable soup with lentils

Serves 4
 2 carrots, pared
 2 potatoes, peeled
 2 sticks celery
 1 parsnip, peeled
 1 leek, well washed
 1 clove of garlic
 2tbsp oil
 1 tin chopped tomatoes
 1 litre/4 cups vegetable stock (for gluten-free soup use home-made or gluten-free stock cubes)
 150g/10tbsp red lentils
 salt and pepper
 1-2tsp chopped thyme
 cress or parsley, chopped
1 Cut the carrots, potatoes, celery and parsnip into pieces and slice the leek. Chop or crush the garlic.
2 Heat the oil in a heavy saucepan, add the vegetables and cook slowly until they are fairly soft but not coloured, stirring frequently. Add the tomatoes and half the stock.
3 Simmer for about 20 minutes until the vegetables are completely soft.
Meanwhile rinse the lentils well and drain. Put them in a pot with the remaining stock and cook for about 10 minutes or until soft.
4 Mash the cooked vegetables with a potato masher or a whisk, or puree the mixture in a food processor if you prefer a smooth soup. Combine with the lentil mixture, adding more stock or water if the soup is too thick.
5 Season to taste with thyme, freshly ground pepper and a little salt if necessary. Sprinkle with the chopped cress or parsley. Serve with some wholemeal or black bread.