Preparation

• Cook the bacon in the oil in a large saucepan or pot over medium heat, stirring occasionally, until it’s brown and crisp, about 8 minutes. Using a slotted spoon, transfer the bacon to a plate lined with paper towels. Add the leek, carrots, and celery to the pan, season with salt and pepper, and cook, stirring occasionally, until the vegetables soften and just start to brown, about 7 minutes. Stir in the cumin and coriander and cook for 30 seconds. Stir in the lentils and 5 cups water and season with salt and pepper. Bring to a boil, reduce the heat to a gentle simmer, cover, and cook until the lentils become tender but not mushy, about 45 minutes. Stir in 1/4 cup of the cilantro and the reserved bacon. Thin with water, if necessary, to get the consistency you like. Taste for salt and pepper.
• In a small bowl, mix the yogurt with the remaining 2 Tbs.cilantro and the mint and season with salt. Ladle the soup into serving bowls, top with a dollop of the yogurt, and serve immediately.