- olive oil
- Sweet potato
- Wash and cut the leeks (white and light green parts).
- Wash and dice the tomatoes.
- Peel and dice the sweet potatoes.
- Heat the oil in a large saucepan or Dutch oven over medium heat. Add the leeks and cook, stirring occasionally, until they begin to soften, 3 to 4 minutes.
- Add the tomatoes and cook, breaking them up with a spoon, for 5 minutes.
- Add 6 cups water and bring to a boil. Stir in the sweet potatoes, kale, lentils, thyme, salt, and pepper. Simmer until the lentils are tender, 25 to 30 minutes.
- Spoon into bowls and serve.