Kue Lembaran Mentega Kecokelatan

Bahan-bahan (24 porsi)

• 1 cup unsalted butter
• 1 cup water
• 2 cups all-purpose flour
• 2 cups granulated sugar
• 2 large eggs
• ½ cup sour cream
• 1 tablespoon vanilla extract
• 1 teaspoon baking powder
• 1 teaspoon salt
• 6 tablespoons unsalted butter
• 6 cups powdered sugar
• 1 teaspoon vanilla extract
• 8 tablespoons milk, (more as needed)