In a large mixing bowl, cream together ½ cup softened unsalted butter, ½ cup granulated sugar, and ½ cup brown sugar until fluffy and light, about 3-5 minutes.

Add 1 large egg and 1 teaspoon vanilla extract, mixing until fully incorporated.

Gradually sift in 2 cups all-purpose flour and 2 teaspoons baking powder, stirring until a soft dough forms.

Divide the cookie dough into two equal disks and wrap each one tightly in plastic wrap. Refrigerate the disks for at least 1 hour.

Once chilled, take one disk out of the fridge and roll it out on a lightly floured surface to a thickness of about ¼ inch.

Brush the rolled dough lightly with melted butter, then evenly sprinkle a mixture of 2 tablespoons cinnamon and ¼ cup brown sugar over the top.

Carefully roll the dough into a tight log, sealing the edges as you go.

With the log formed, pinch the ends to seal them and wrap it in plastic wrap. Chill the log in the refrigerator for another 30 minutes.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Remove the chilled log from the refrigerator and use a sharp knife to slice it into ½-inch rounds.

Place the cookie slices on the prepared baking sheet, leaving space between each. Bake for 12-15 minutes or until the edges are lightly golden.

While the cookies are baking, whisk together 1 cup powdered sugar and 2 tablespoons milk in a small bowl until smooth and creamy.

Once the Cinnamon Roll Cookies have cooled slightly, drizzle the icing generously over the top.