Preheat the oven to 350°F (175°C).

In a large mixing bowl, cream together the butter and brown sugar until light and fluffy (about 2-3 minutes).

Beat in the egg until well combined.

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

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

Using a cookie scoop or spoon, drop tablespoons of dough onto a parchment-lined baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes, until edges are golden brown and centers look slightly underbaked.

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