Stewed Lentils with Celery Root and Walnut Oil

Lentils aren’t a particularly showy food, but they have an earthy, reliable taste that’s good to return to every now and then. Celery root, or celeriac, is seasonal during the same months one would be inclined to cook lentils, and the two go well together. Pressed in the fall, even the walnut oil is somewhat seasonal. Its heavy fragrance and high viscosity also seem best enjoyed in the colder months of the year.