Ingredients:
Broth
2 whole chicken legs
1 small yellow onion, quartered
1 (5-inch) piece ginger, smashed
3 garlic cloves, smashed
1 teaspoonwhole black peppercorns
1 teaspoonkosher salt
Soup
Kosher salt and freshly ground black pepper
2 medium russet potatoes, peeled and diced into ½-inch cubes
1/2 cupred lentils, rinsed
2 tablespoonsneutral oil (such as sunflower or grapeseed)
1/2 teaspoonblack mustard seeds
1/2 teaspooncumin seeds
1/4 teaspoonground turmeric
Plain yogurt, for serving
Torn cilantro, for serving
Thinly sliced Thai green chiles, for serving
Directions:
Make the broth: In a medium Dutch oven, combine all the ingredients. Slowly pour 6 cups of water on top. Bring to a boil over high heat. If foamy white scum floats to the top, skim it off with a ladle, spoon, or small sieve. (Don’t worry about getting all of it—just try to get as much as you can without losing too much broth.) Reduce heat to maintain a gentle simmer, cover with a tight-fitting lid, and cook for 1½ hours, until the chicken is tender and the broth is flavorful.
Strain the broth into a large heatproof vessel (I use a big metal bowl). Return the broth to the Dutch oven. Transfer the chicken to a plate and discard the aromatics.
Make the soup: Bring the broth to a gentle simmer. Taste the broth and season with salt and pepper as needed. Add the potatoes and lentils and simmer until the potatoes are tender, about 20 minutes.
Meanwhile, pick the chicken meat off the bone, trying to maintain large chunks. Reserve the meat and discard the bones and skin.
Once the potatoes and lentil are done, in a small skillet, heat the oil over medium high heat until it shimmers. Add the black mustard seeds, cumin seeds, and turmeric. Cook, stirring constantly, until fragrant and the mustard seeds start to pop, about 1 minute. Scrape the spiced oil into the soup and stir to incorporate. Add the reserved chicken meat and stir until warmed through. Taste and season with salt and pepper as needed.
Divide the soup into bowls and top with yogurt, cilantro, and chiles. Store ungarnished leftovers in the fridge for up to 5 days or in the freezer for 3 months.