Celeriac and lentils with hazelnut and mint

Celeriac is probably my favourite root. It is delicate, yet very nutty, and has an elegant oily smoothness. Like all good vegetables, it is marvellous simply with a bit of olive oil. Here it works with the lentils and nuts to create a hearty autumn main course. Serve it warm, with a radish, cucumber and dill salad dressed with soured cream and olive oil. Or, allow it to cool down, then take it to work for lunch or on a picnic.