Step 1: Prepare the Dough

1. Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. In a medium bowl, whisk together flour, baking powder, and salt. Set aside.

Step 2: Cream Butter and Sugar

1. In a large bowl, cream the softened butter and granulated sugar until light and fluffy.
2. Add the egg and vanilla extract, beating until fully combined.

Step 3: Combine Wet and Dry Ingredients

1. Gradually add the dry ingredients to the wet mixture, mixing until a soft dough forms.

Step 4: Roll and Fill

1. On a lightly floured surface, roll the dough into a 1/4-inch-thick rectangle.
2. Brush the dough with melted butter, then evenly sprinkle the cinnamon-sugar mixture over the surface.

Step 5: Form the Spirals

1. Roll the dough tightly into a log and slice it into 1/2-inch thick rounds.
2. Place the slices onto the prepared baking sheet.

Step 6: Bake and Cool

1. Bake for 10–12 minutes, or until the edges are golden.
2. Let cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.