Ingredients (Serves 4-6)
4 med Desiree or Belle de Fontenay, weighing about 450 g in total
300 ml full fat milk
100 ml double cream
Lots of nutmeg
100 g Gruyere
2 garlic cloves, peeled
S&P (preferably white pepper)
Preheat the oven to 120 C/100C fan/250 F
Prepare the potatoes:
Peel the potatoes and slice them with a mandolin. Do not wash the potato slices, as you need to keep the starch in them to help thicken the cream.
On a medium heat, in a medium saucepan, bring the milk and cream to the boil. Add the sliced potatoes and stir to coat them with the cream. Season with lots of nutmeg, 5 pinches of salt, and 2 pinches of pepper.
Lower the heat and simmer for 8-10 min, stirring every 2 min to prevent the mixture sticking to the base of the pan and to distribute the heat throughout the potatoes. Stir in the grated cheese and then remove the pan from the heat.
Bake the gratin:
Rub a 20 cm (8 in) gratin dish with the garlic. With a spatula, spread the potato mixture out evenly in the dish. Place in the oven and bake for 35 min; there should be tiny bubbles on the surface of the dish.
Preheat the grill about 10 min before the gratin is cooked.
The gratin is cooked when the tip of a sharp knife cuts into it with little resistance (you shouldn't feel the layers).
To brown the top, place under a hot grill for 2-3 min. (Optional)
Leave to rest for 5 min before serving.
