Celeriac and Anchovy Gratin

Make Ahead – Assemble gratin up to 2 days ahead, press food wrap onto surface to submerge celeriac and refrigerate. To cook, add extra liquid if needed, dot with butter and then bake, allowing an extra 20 minutes or so until piping hot.

Store – Refrigerate leftovers, covered, for up to 2 days. Reheat in a microwave or transfer to ovenproof dish, cover with foil and heat in 180°C/160°C Fan oven until piping hot.

Freeze – Freeze leftovers in airtight container for up to 3 months. Defrost overnight in fridge. Reheat as above.