Preheat oven to 350°F and line baking sheets with parchment paper.

In a large bowl using an electric mixer, beat softened butter and granulated sugar until creamy, about 2 minutes.

Add egg and vanilla extract, beating until combined.

In a medium bowl, whisk together flour, baking powder, and salt. Gradually add to butter mixture and mix on low until a soft dough forms.

Divide dough in half. Roll each half between parchment sheets into a 15×10-inch rectangle.

In a small bowl, mix melted butter, brown sugar, and cinnamon until combined. Spread evenly over dough rectangles.

Roll each rectangle tightly into a log, starting from a long edge. Wrap logs in plastic and refrigerate or freeze for at least 30 minutes.

Stir together coating sugar and cinnamon in a small bowl.

Slice chilled logs into 1/4-inch thick rounds, then dip the edges in the coating mixture.

Place cookies 2 inches apart on prepared baking sheets.

Bake for 12-14 minutes until the edges are lightly golden and the centers remain soft.

Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack.