Low-Fat Scalloped Potatoes

INGREDIENTS

• 1/4 cup grated gruyere cheese
• 3 pounds Yukon gold potatoes, peeled and thinly sliced
• 2 tablespoons unsalted butter, plus more for the dish
• Kosher salt
• 1 cup whole milk, at room temperature
• 1 cup low-fat milk (1%), at room temperature
• Freshly ground pepper
• 1/4 teaspoon freshly grated nutmeg
• 2 tablespoons all-purpose flour