Kentang Bergigi Parmesan Krim

Bahan-bahan (6 porsi)

• 2 tablespoons unsalted butter
• 2 tablespoons all-purpose flour
• 1 teaspoon salt
• ½ teaspoon ground black pepper
• 2 cup heavy whipping cream
• ¼ cup grated parmesan cheese
• 2 pounds peeled and sliced russet potatoes (sliced about ⅕ inch thick)
• 1 cup shredded mozzarella cheese
• ¼ cup grated parmesan cheese
• chopped chives (for garnish)