- 2 tablespoons canola oil or peanut oil
- 1 medium or large onion, chopped
- 4 garlic cloves, minced
- Salt to taste
- 2 teaspoons cumin seeds, lightly toasted and ground
- 2 teaspoons coriander seeds, lightly toasted and ground
- 2 teaspoons hot curry powder
- 1 (28-ounce) can chopped tomatoes with juice
- 1 pound red lentils (about 2 1/8 cups), washed and picked over
- 2 quarts water or chicken stock
- ¼ teaspoon ground black pepper (more to taste)
- Cayenne to taste (optional)
- Juice of 1/2 lime
- Heat the oil in a large, heavy soup pot over medium heat and add the onion. Cook, stirring, until tender, about 5 minutes, and add the garlic, 1/2 teaspoon salt, the cumin, coriander, and curry powder. Stir together for about a minute, until the garlic is fragrant, and stir in the tomatoes with their juice. Bring to a simmer and cook, stirring often, for 10 minutes, until the tomatoes have cooked down slightly. Add salt to taste.
- Stir in the lentils and water or chicken stock. Bring to a boil, reduce the heat, cover and simmer 30 minutes. Add salt to taste and continue to simmer for 15 to 30 minutes, until the lentils have fallen apart and thickened the soup. Using the back of your spoon, mash the lentils against the side of the pot to thicken the soup further. Add the pepper, taste, and add cayenne if you want more spice. Taste and adjust salt. Stir in the lime juice.
- If you wish, puree with an immersion blender or in batches in a blender, holding a towel over the lid to prevent hot soup from splashing out, and return to the pot. Heat through and serve, topping each bowl with a dollop of yogurt and a generous sprinkling of chopped cilantro.