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

2. In a medium bowl, whisk together the flour, baking soda, salt, and ground cinnamon.

3. In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar until light and fluffy.

4. Add the egg and vanilla extract, then mix until smooth and fully combined.

5. Gradually add the dry ingredients to the wet ingredients and mix just until a soft dough forms.

6. Scoop the dough into even portions, about 1 1/2 tablespoons each, and place them on the prepared baking sheets.

7. Roll the tops lightly in cinnamon sugar if using.

8. Bake for 9 to 11 minutes, until the edges are lightly golden and the centers still look slightly soft.

9. Let the cookies cool on the pan for 5 minutes, then transfer them to a wire rack to cool completely.