This soup is rich and flavorful and hits the spot on a chilly night. It’s heavenly served with little scoops of leftover or freshly-made mashed potatoes in the bowls. This recipe is flexible and forgiving. Try adding chickpeas or steamed cooked greens for variety. Whether prepared all day in the slow cooker, or on the stove on a weekend afternoon, Perfect Lentil Soup with Mashed Potatoes takes comfort food to a whole new level.