Rub your dish with the clove of peeled garlic and then grease it with butter

Put a layer of Gruyere in the bottom of the dish (if using) and reserve at least half of the cheese for the top.

Arrange the potatoes evenly in the dish to a depth of around 4-5 cm.

Mix the 2 egg with the milk and add the salt and nutmeg.

Warm the cream and whisk in the egg mixture.

Pour this over the potatoes and dot with knobs of the remaining butter. Add cheese to the top if using

Cook in a preheated oven at 220C for about 30 minutes.

Check the colour isnt getting to dark on top and cook for a further 20 minutes. Cover the top in foil during this time if necasary. Check for splitting also and pull if going to far.

Cool on racks, then in the fridge overnight. Portion the following day into approx 150 gram portions.

Tray and re-heat on site 15 minutes prior to serving.