3 tablespoons olive oil, more for drizzling
1 large onion, chopped
2 garlic cloves, minced
1 tablespoon tomato paste
1 teaspoon ground cumin
1/4 teaspoon kosher salt, more to taste
1/4 teaspoon ground black pepper
Pinch of ground chili powder or cayenne, more to taste
1 quart chicken or vegetable broth
1 cup red lentils
1 large carrot, peeled and diced
Juice of 1/2 lemon, more to taste
3 tablespoons chopped fresh cilantro.
In a large pot, heat 3 tablespoons oil over high heat until hot and shimmering. Add onion and garlic, and sauté until golden, about 4 minutes.
Stir in tomato paste, cumin, salt, black pepper and chili powder or cayenne, and sauté for 2 minutes longer.
Add broth, 2 cups water, lentils and carrot. Bring to a simmer, then partially cover pot and turn heat to medium-low. Simmer until lentils are soft, about 30 minutes. Taste and add salt if necessary.
Using an immersion or regular blender or a food processor, purée half the soup then add it back to pot. Soup should be somewhat chunky.
Reheat soup if necessary, then stir in lemon juice and cilantro. Serve soup drizzled with good olive oil and dusted lightly with chili powder if desired.