Stir in the tomato paste and cook for a minute more. Next, add the crushed tomatoes, green lentils, and vegetable stock. Bring to a boil, then reduce heat and simmer for about 30-35 minutes or until the lentils are tender.
1 tablespoon tomato paste
2 cans (14 oz / 400 g) crushed tomatoes
1 ½ cup green lentils
4 cups vegetable stock