Lentil soup recipes can range from super hearty to watery and tasteless. This soup is the best of both worlds: filling and flavorful, yet light and vegetarian.
- 1Heat the oil in a large saucepan over medium heat until shimmering, about 3 minutes. Add the celery, carrot, and onion and cook, stirring occasionally, until the vegetables have softened, about 10 minutes. Stir in the garlic and cook until fragrant, about 1 minute. Season with several generous pinches of salt and pepper.
- 2Add the broth, tomatoes with their juices, lentils, bay leaf, and thyme and stir to combine. Cover and bring to a simmer, about 15 minutes. Once simmering, reduce the heat to low and continue simmering, covered, until the lentils and vegetables are soft, about 15 minutes more.
- 3Taste and season with more salt or pepper as needed, then stir in the vinegar. Add the spinach and stir until wilted. If you prefer a creamier texture, purée half of the soup in a blender and add it back to the pot.