Preheat your oven to 375°F (190°C).

Peel and thinly slice the Yukon Gold potatoes to approximately 1/8 inch thick. Set aside in cold water to prevent browning.

Clean the leeks thoroughly, slicing them lengthwise and rinsing under cold water to remove grit. Drain and set aside.

In a medium skillet, melt 2 tablespoons of unsalted butter over medium heat. Add leeks and sauté for 3-4 minutes until soft. Add minced garlic and cook for another minute.

Pour in half a cup of white wine to deglaze the pan, letting it reduce slightly. Stir in 1 cup of heavy cream and your preferred seasonings, allowing it to simmer for 3-4 minutes until thickened.

Remove the cream sauce from heat, and stir in 3/4 of the grated cheese until melted and smooth.

In your greased baking dish, spread a layer of the creamy leek mixture on the bottom. Arrange potato slices upright in a circular fashion. Pour the remaining creamy mixture over the potatoes.

Sprinkle the remaining cheese evenly over the top. Cover with foil to trap moisture during the first half of the baking process.

Place the covered baking dish in the oven and bake for 30 minutes.

After 30 minutes, remove the foil and continue to bake for another 20 minutes or until the top is golden and bubbly.

Allow the gratin to cool for a few minutes before serving.