1/4 cup butter
2 large sweet potatoes, peeled and chopped
3 large carrots, peeled and chopped
1 apple, peeled, cored and chopped
1 onion, chopped
1/2 cup red lentils
1/2 teaspoon minced fresh ginger
1/2 teaspoon ground black pepper
1 teaspoon salt
1/2 teaspoon ground cumin
1/2 teaspoon chili powder
1/2 teaspoon paprika
4 cups vegetable broth
plain yogurt or sour cream
- Melt the butter in a large, heavy bottomed pot over medium-high heat. Place the chopped sweet potatoes, carrots, apple, and onion in the pot. Stir and cook the apples and vegetables until the onions are translucent, about 10 minutes.
- Stir the lentils, ginger, ground black pepper, salt, cumin, chili powder, paprika, and vegetable broth into the pot with the apple and vegetable mixture. Bring the soup to a boil over high heat, then reduce the heat to medium-low, cover, and simmer until the lentils and vegetables are soft, about 30 minutes.
- Working in batches, pour the soup into a blender, filling the pitcher no more than halfway full. Hold down the lid of the blender with a folded kitchen towel, and carefully start the blender, using a few quick pulses to get the soup moving before leaving it on to puree. Puree in batches until smooth and pour into a clean pot. Alternately, you can use a stick blender and puree the soup right in the cooking pot.
- Return the pureed soup to the cooking pot. Bring back to a simmer over medium-high heat, about 10 minutes. Add water as needed to thin the soup to your preferred consistency. Serve with yogurt for garnish.