Step 1

Add sliced potatoes to a bowl and cover them with water. Wrap the bowl with plastic wrap and microwave it for 5 minutes. Drain the water and set aside.

Step 2

Preheat the oven to 200°C (410°F).

Step 3

Melt the butter in a skillet over medium heat. Add the flour, followed by the milk. Continuously stir the mixture until the flour is dissolved. Season it with salt, ground black pepper and grated Parmesan cheese. Stir well.

Step 4

Add potato slices to the white sauce and stir to coat all slices evenly. Turn off the heat. Transfer the potato slices to a baking dish and pour the remaining white sauce over them.

Step 5

Bake it for 10 to 15 minutes until the cheese melts and the top is golden brown.

Step 6

Remove the potato gratin from the oven, rest for a few minutes, then serve.