• Dough Preparation:
• In a medium-sized mixing bowl, amalgamate the flour, baking powder, and salt.
• Using an electric mixer with a paddle attachment in a large bowl, cream together the butter and sugar until achieving a smooth consistency. This should take approximately 2 minutes.
• Incorporate the egg and vanilla into the butter mixture, ensuring a homogenous blend. Should there be any remnants on the bowl's sides or base, scrape and mix once again for uniformity.
• Gradually introduce the earlier prepared dry ingredients into the wet mixture. Combine on a low setting until fully integrated. If the dough appears excessively pliable and sticky, an additional tablespoon of flour may be incorporated.
• Shaping and Filling:
• Equally segregate the dough into two portions. Each portion should be rolled out into a rectangle, roughly measuring 9x7 inches, on a floured surface, ensuring a thickness of about 1/4 inch. Evenly disseminate 1 tablespoon of the melted butter on each rectangle. Subsequently, distribute the combined granulated sugar and cinnamon over the butter layer.
• With precision and care, roll each rectangle into a tight log measuring 9 inches in length. If any cracks appear, gently smoothen them. It is advisable to refrigerate the logs for a minimum of 2 hours to ensure firmness. If preferred, the logs may also be stored in the freezer for future use, for up to 3 months.
• Preheat the oven to a temperature of 350°F (177°C) and line a baking sheet with either parchment paper or a silicone mat for optimal results.
• Remove the logs from the refrigerator and slice them into half-inch thick rounds. Arrange the rounds on the prepared baking sheet, maintaining a distance of approximately 2 inches between each.
• Bake the cookies for a span of 10-11 minutes, or until the sides exhibit a light brown hue. Post baking, permit the cookies to cool on the sheet for 5 minutes, and thereafter, transfer them to a wire rack for complete cooling.

Icing Preparation:

• Whisk the confectioners’ sugar, milk, and vanilla extract together until achieving a smooth icing. Once the cookies are cooled, drizzle them with this icing.