SPINACH SOUP WITH CORIANDER, CINNAMON AND ALLSPICE

Steps:

• Heat the olive oil over medium heat in a large, heavy soup pot or Dutch oven, and add the onion and celery. Cook, stirring, until tender, about 5 minutes. Add a generous pinch of salt and the garlic and cook, stirring, until the garlic smells fragrant, 30 seconds to 1 minute.
• Add the stock, rice, bouquet garni, and salt to taste, and bring to a boil. Reduce the heat, cover and simmer 30 minutes. Remove the bouquet garni. Stir in the spinach and spices, cover and simmer 5 minutes, stirring once or twice. The spinach should wilt but should maintain its bright color.
• Using a hand blender that has a powerful motor, or in batches in a regular blender, purée the soup. If using a regular blender, fill only halfway and cover the top with a towel pulled down tight, rather than the lid, because hot soup will push the top off if the blender is closed airtight. Return to the pot and heat through, stirring. Whisk 1 teaspoon cornstarch into 1 cup of the yogurt, and whisk into the soup. Season to taste with salt and pepper.
• If you want a pungent, garlicky yogurt garnish, mash the remaining garlic to a paste with a pinch of salt in a mortar and pestle. Stir into the remaining yogurt. Serve the soup, garnishing each bowl with a swirl of the yogurt and a sprinkling of chopped walnuts.