Preheat your oven to 350°F (175°C).

Cream together the brown sugar and butter until light and fluffy.

Beat in the egg and vanilla extract until well combined.

In a separate bowl, whisk together the flour, baking powder, salt, and ground cinnamon.

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

Roll the dough out on a floured surface to about 1/4 inch thick.

Cut out cookie shapes with your favorite cookie cutter and place them on a baking sheet lined with parchment paper.

Bake for 10-12 minutes or until the edges turn golden brown.

Let the cookies cool completely before frosting.

For the frosting, combine powdered sugar and milk until smooth, then frost the cooled cookies.