Preheat oven to 350°F and line a baking sheet with parchment paper
In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add egg and vanilla to butter and sugars
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
In a small bowl, combine the granulated sugar and ground cinnamon for the coating
Roll the cookie dough into 1 ½-inch balls. Roll each dough ball in the cinnamon-sugar mixture to coat
Place the coated dough balls on the prepared baking sheet, about 2 inches apart
Bake for 10-12 minutes or until the edges are set but the centers are still slightly soft. The cookies will firm up as they cool.
Let the cookies cool on the baking sheet for a few minutes, then transfer them to a wire rack to cool completely