Creamy potato gratin for Christmas (make-ahead)

Name: Creamy potato gratin for Christmas (make-ahead)
Prep time: 20 min
Cook time: 70 min
Total time: 90 min
Yield: 6
Ingredients: 1.2 kg waxy or all-rounder potatoes (such as Charlotte or Maris Piper); 400 ml double cream; 200 ml whole milk; 2 garlic cloves; 2 sprigs of fresh thyme (optional); a pinch of grated nutmeg; 100 g Gruyère or mature Cheddar, grated; 15 g butter, for the dish; salt and black pepper

Prep: 20 min · Cook: 70 min · Makes: 6 · For: For grown-ups

A good potato gratin is the side dish that disappears first at Christmas dinner. Thin slices of potato bake slowly in garlicky cream until they are meltingly soft, while the top turns golden and a little crisp at the edges.

The trick in this recipe is to simmer the potato slices in the cream for a few minutes before they go into the oven. It gives you a thicker sauce, more even cooking and a gratin that is ready on time, which matters when the oven is crowded.

It goes with almost everything on the festive table: roast turkey or a joint of beef, a whole salmon, or a mushroom Wellington for the vegetarians.

Tips for a perfect gratin

Choose the right potato. All-rounders hold their shape but still soak up the cream. Very floury potatoes can turn to mush.
Slice evenly. Even slices cook at the same speed, so there are no hard bits in the middle.
"Season the cream well. Taste it before the potatoes go in: it should taste slightly too salty, because the potatoes absorb a lot."

Variations

Without cheese: leave the cheese out for a classic, silky gratin in the French style.
Lighter: use half cream and half milk. It is a little less rich but still lovely.
With leeks: soften two sliced leeks in butter and layer them between the potatoes.

Little helpers

Children can help rub the dish with garlic, butter it and scatter the cheese on top. The mandoline and the hot pan are jobs for a grown-up.

Ingredients

1.2 kg waxy or all-rounder potatoes (such as Charlotte or Maris Piper)
400 ml double cream
200 ml whole milk
2 garlic cloves
2 sprigs of fresh thyme (optional)
a pinch of grated nutmeg
100 g Gruyère or mature Cheddar, grated
15 g butter, for the dish
salt and black pepper

Method

Heat the oven to 180°C (160°C fan, gas mark 4). Halve one garlic clove, rub the cut side all over a baking dish of about 20 x 30 cm, then butter the dish.
Peel the potatoes and slice them thinly, about 3 mm thick. A mandoline is quickest, but use the hand guard. Do not rinse the slices; their starch thickens the sauce.
Put the cream, milk, the remaining garlic (crushed), thyme leaves, nutmeg, 1 tsp salt and plenty of pepper in a large pan and bring to a gentle simmer.
Add the potato slices to the pan and simmer for 5 minutes, stirring carefully, so they start to soften and the cream thickens.
Tip everything into the dish and press the slices flat with the back of a spoon so they sit in neat layers under the cream.
Cover with foil and bake for 40 minutes. Remove the foil, scatter over the cheese and bake for another 25-30 minutes, until golden and a knife slides through the potatoes easily.
Let it rest for 10 minutes before serving so the layers set and slice cleanly.

Questions

Can I make potato gratin the day before?

Yes. Bake it completely, let it cool, cover and chill. On the day, reheat it covered at 160°C (140°C fan, gas mark 3) for about 30 minutes, then uncover for the last 10 minutes to crisp the top.

Why is my gratin watery?

Usually the potatoes were rinsed, sliced too thick or not baked long enough. Simmering the slices in the cream first, as in this recipe, almost always fixes it.

Can I freeze it?

You can, but the texture of potatoes and cream changes a little after freezing. It is better to make it one or two days ahead and keep it in the fridge.