This is a version of gratin dauphinois. The cheese transforms it into a -- very rich -- main course. It also introduces acidity to the dish. Simmering in milk and cream, potatoes soften quickly, but with cheese there as well they can retain their crunch for a long time. Even if you slice them thinly, you may find that you need to cook the dish for a good hour and a half. For 4.
Small knob of butter
700g Charlotte or similar new potatoes
1 clove garlic, chopped
150g Gruyere or other hard cheese
250ml double cream
Pinch of nutmeg
Butter a gratin dish. Scrape or peel the potatoes, according to taste, and slice them thinly. Layer them in the dish with the cheese and the chopped garlic. (Add salt if you like, but remember that the cheese is salty.) Pour over the cream, and grate over a little nutmeg.
Bake in the oven, starting at gas mark 4/180C and turning down the heat after 30 minutes or so if you think that the dish is bubbling too vigorously.
You may think, before you put the dish in the oven, that it does not contain enough liquid and that the top potatoes are not submerged. Wait until it starts simmering. You will probably find that more liquid has materialised. If not, pour over a little milk.
Cook until the potatoes are soft, and sitting in thickened liquid.