Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

In a mixing bowl, whisk together the flour, baking soda, cream of tartar, salt, and cinnamon.

In another bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.

Beat in the egg and vanilla extract until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Fold in the chopped apple.

In a small bowl, mix together the granulated sugar and cinnamon for the topping.

Using a cookie scoop, drop dough onto the prepared baking sheet. Roll each ball in the cinnamon-sugar mixture.

Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden.

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