Potato, celeriac and leek gratin with sage and feta

Serve this delicious dish with grilled meats or with crusty bread and a salad for a great lunch.

Serves 4-6 as a side dish

vegetable oil spray
3 baking potatoes, sliced into 5 mm thick slices
100g feta cheese, crumbled
freshly ground black pepper, to taste
½ celeriac bulb, peeled and thinly sliced
½ leek, thinly sliced and rinsed
150 ml boiling water
sprig of sage

Preheat oven to 180°C.
Spray a round 22 cm diameter baking dish (about 1.5 L capacity) with oil.
Arrange half the potato slices on the bottom of the dish.
Scatter half the feta on top and sprinkle with pepper.
Lay celeriac slices on top followed by leeks and remaining feta.
Lay remaining potato slices on top, pour in boiling water, then add pepper.
Lightly spray potatoes with oil. Place a sheet of non-stick baking paper the same size as the dish on top of the potatoes. Cover with aluminium foil and seal tightly.
Place in preheated oven and bake for about 1½ hours, then remove foil and baking paper. Place under a preheated grill, and grill until potatoes are golden.
Garnish with sage and serve.