FOR THE COOKIES: – 1 cup unsalted butter, softened – 1 1/3 cups sugar – 2 large egg – 2 teaspoons vanilla extract – 3 cups all-purpose flour – 1/2 teaspoon baking powder – 1/2 teaspoon kosher salt FOR THE FILLING: – 1/4 cup sugar – 1 Tablespoon ground cinnamon – 2 Tablespoons unsalted butter, melted and cooled FOR THE ICING: – 1 cup confectioners’ sugar, sifted – 1 Tablespoon unsalted butter, melted – 2 Tablespoons whole milk