Making the Cookies

• Whisk the flour, baking powder, and salt together in a medium bowl. Set aside.
• In a large bowl, beat the butter and sugar together on high speed until smooth and creamy, about 2 minutes. Add the egg and vanilla and beat on high speed until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl and beat again as needed to combine.
• Add the dry ingredients to the wet ingredients and mix on low until combined. If the dough seems too soft and sticky for rolling, add 1 more tablespoon of flour.
• Divide the dough into 2 equal parts. Roll each portion out into a rectangle onto a floured surface to about ¼" thickness. Spread melted butter onto each rectangle and sprinkle the cinnamon sugar mixture evenly over each.
• Roll up each rectangle into a 9-inch log. Chill the logs of dough for at least 2 hours or freeze for up to 3 months.
• Preheat oven to 350°F (177°C). Line a large baking sheet with parchment paper.
• Remove dough logs from the refrigerator and cut into ½ inch slices. Place slices onto baking sheets about 2 inches apart.
• Bake for 10-11 minutes, until lightly browned on the sides. Let cool on the baking sheet for 5 minutes then transfer to a wire rack to cool completely.
• Whisk all of the icing ingredients together and drizzle over cooled cookies.
• Cover and store cookies at room temperature for up to 5 days.