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

In a medium bowl, whisk together the flour, baking powder, salt, and ground cinnamon until well combined.

In a large mixing bowl, cream together the softened unsalted butter, granulated sugar, and brown sugar until light and fluffy.

Add the egg and vanilla extract to the butter mixture, beating well after each addition until smooth.

Gradually add the dry mixture to the wet mixture, stirring until just combined.

In a small bowl, mix the brown sugar and ground cinnamon for the filling until well combined.

Roll out half the dough onto a lightly floured surface into a rectangle about ¼ inch thick and sprinkle half the cinnamon filling over it.

Roll the dough tightly into a log and slice into 1-inch rounds.

Place the sliced cookies onto the prepared baking sheet, ensuring enough space to spread.

Bake in the preheated oven for 10-12 minutes or until the edges are golden brown.

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