CELERIAC & SWEET POTATO BOULANGÈRE

Neven says: “This hassle-free dish is perfect for the Christmas table. The layered up celeriac, sweet potatoes and onions absorb all the stock. It can be made in advance and left to cool completely before covering with cling- lm and storing in the fridge for up to three days before you want to use it. Reheat covered with tin foil in a preheated oven set to 180°C (350°F/gas mark 4) for 30 minutes, until piping hot”

SERVES 8 10 2 tbsps rapeseed oil, plus extra for greasing

3 onions, thinly sliced (on a mandolin is best)

3 garlic cloves, thinly sliced

2 tbsps roughly chopped fresh at-leaf parsley

1 tbsp chopped fresh mixed herbs (use a mixture of sage, rosemary and thyme) 1kg sweet potatoes, peeled and thinly sliced (on a mandolin is best)

1 large celeriac, peeled and thinly sliced (on a mandolin is best)

900ml chicken or vegetable stock

50g butter, diced

25g stale white breadcrumbs (sourdough is best)

Sea salt and freshly ground black pepper

Method

1 Pre-heat the oven to 200°C (400°F/gas mark 6).

2 Heat the oil in a frying pan set over a medium heat, then sauté the onions, garlic and herbs for 10 minutes, until soft and lightly golden. Season to taste.

3 Layer the sweet potatoes in a large baking dish with the onions and celeriac. Season each layer as you go and nish with an attractive overlapping layer of the sweet potatoes. Pour over the stock and top with knobs of butter.

4 Rub some foil with oil and place it over the dish, oil side down, and seal tightly. Bake in the oven for 45 minutes, then remove the foil and press the potatoes down with a sh slice. Scatter over the breadcrumbs and bake for another 15-20 minutes, until golden. Serve at once or leave to cool completely before covering and storing in the fridge until needed.