Lentil and vegetable soup

Ingredients

• 1 teaspoon olive or vegetable oil
• 1 small onion, peeled and roughly chopped
• 1 medium carrot, peeled and sliced
• 1 small parsnip, peeled and chopped
• 1 x 400g can chopped tomatoes
• 250ml reduced-salt vegetable stock
• 1 dried bay leaf
• Sprinkle of dried thyme
• 30g red lentils, rinsed