Ultimate Easy Bake Duplex Crème Cookies

Ingredients

• 1 cup (226g) unsalted butter, softened
• 1 cup (200g) granulated sugar
• ½ cup (100g) packed brown sugar
• 2 large eggs
• 2 teaspoons vanilla extract
• 2 cups (250g) all-purpose flour
• ¾ cup (75g) unsweetened cocoa powder
• 1 teaspoon baking soda
• ½ teaspoon salt
• 1 cup (120g) powdered sugar
• ½ cup (115g) unsalted butter, softened
• 1-2 tablespoons milk (as needed for consistency)