Lentil Soup with Spinach

Name: Lentil Soup with Spinach
Ingredients: 2 cups (14 oz./440 g) brown lentils; 3 Tbs. olive oil; 1 yellow onion, chopped; 1 carrot, peeled and chopped; 2 celery stalks, chopped; 3 garlic cloves, minced; 1 tsp. ground cumin; 1 tsp. ground coriander; 1 tsp. sweet paprika; 3/4 tsp. salt; 1/4 tsp. freshly ground pepper; 1 can (28 oz./875 g) diced tomatoes with juices; 1/4 cup (2 fl. oz./60 ml) Williams-Sonoma Chicken Stock Concentrate; 6 cups (48 fl. oz./1.5 l) water; 6 oz. (185 g) spinach, stemmed and coarsely chopped; 2 tsp. sherry vinegar, or more taste