This Indian-style soup has an almost creamy quality thanks to yellow lentils. (If you can't get them, swap in yellow split peas, and cook them 10 minutes or so more.)
Make the soup: Heat oil and coriander seeds in a medium saucepan over high heat for 1 minute. Add stock and lentils. Bring to a simmer. Reduce heat, and simmer gently, partially covered, until lentils are tender and most of the liquid is absorbed, 40 to 50 minutes. Stir in 1 teaspoon salt.
Meanwhile, make the chutney: Pulse cilantro, lime juice, oil, and ginger in a food processor until cilantro is finely chopped. Serve soup topped with chutney.
This soup is thick enough to scoop up with papadums (Indian crackers), celery sticks, or cucumber spears.