Potato Leek Gratin with White Cheddar Cheese

Bahan-bahan (8 porsi)

• 4 medium leeks, (white and pale green part only, halved and very thinly sliced (4 to 5 cups))
• 2 tablespoons unsalted butter
• 2 medium garlic cloves, (minced)
• salt and white pepper, (to taste)
• 1 pinch freshly grated nutmeg
• 1½ to 1¾ pounds Russet potatoes
• 1 cup heavy whipping cream
• 1 cup whole milk
• 6 ounces sharp white cheddar cheese, (shredded (about 1½ cups))