Potato Gratin

For 4 servings:

500g potatoes
100g leek
Grand Parmesan cheese
1 tbsp butter + extra butter for greasing and drizzling
100ml milk
150ml cream
1 clove garlic
A pinch of grated nutmeg
Salt and pepper

Peel the raw potatoes and slice them thinly.
Cut the leek into strips and sauté it with a finely chopped garlic clove in butter.
Pour in the milk and cream and bring to a boil.
Add the potatoes and season with salt, pepper, and nutmeg. Cook for about 6 minutes, stirring frequently.
Grease a baking dish with butter, add the potato mixture, sprinkle with Parmesan, dot with butter, and bake in a preheated oven at 180°C (356°F) for about 20 minutes