1 (15-ounce) can diced tomatoes with their juices (I used fire-roasted)
1¼ cups lentils (any color except red), rinsed
1 teaspoon thyme
½ Tbsp red wine vinegar or sherry vinegar
2 ounces spinach leaves (about ½ a bunch) optional
Instructions
Heat the oil in a large soup pot over medium heat. Add the celery, carrots, 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. Add potato, ½ tsp of salt and pepper, broth, water and thyme. Bring to a boil and then reduce heat and simmer gently for 10 minutes.
Add the tomatoes with their juices and the lentils and stir to combine. Bring to a boil and then cover, turn heat to low and simmer covered for about 25-30 minutes or until the lentils are soft.