Combine celeriac and leek with mature cheddar for an indulgent Christmas side dish. A spoonful of mustard or horseradish stirred through the cream wouldn’t go amiss
Prep:25 mins
Serves 8
25g butter2 leeks, outer layer removed, washed of any grit and sliced into ringssmall handful rosemary leaves, roughly chopped1 bay leaf300ml double cream300ml milk1 celeriac (about 500g), peeled, quartered and thinly sliced100g cheddar or gruyère, coarsely grated
STEP 1Heat the butter in a saucepan. Add the leeks, rosemary and bay leaf, then cover and cook very gently over a medium-low heat for 15-20 mins until the leeks are soft. Pour over the milk and almost all of the cream, then season and bring to the boil. Remove from the heat and leave to cool a little, then scoop out the bay leaf.STEP 2Pour a little of the leek mixture into an ovenproof gratin dish. Arrange a layer of celeriac in the dish, then season. Spoon over some more of the leek mixture and scatter with a little cheese. Repeat the process, alternating between layers of the leek mixture, cheese and celeriac slices, then finish with a drizzle of cream and the last of the cheese. Can be prepared up to a day ahead and kept in the fridge. STEP 3Heat oven to 180C/160C fan/gas 4. Bake the gratin for 1 hr-1 hr 15 mins until the top is golden and the celeriac is tender when poked with a knife. If the gratin is browning a little too much, cover the dish in foil. Can be chilled, then reheated in a microwave or oven on a low heat with a drizzle more cream.
