Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

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

In another bowl, beat the softened butter and sugar together until creamy.

Add the egg and vanilla extract to the butter mixture and mix until combined.

Gradually add the dry ingredients to the wet ingredients and mix until just combined.

Fold in the diced peaches gently.

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

Using a cookie scoop, portion out the dough and roll into balls.

Roll each ball in the cinnamon sugar mixture until fully coated.

Place the coated dough balls on the prepared baking sheet, spacing them about 2 inches apart.

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

Remove from the oven and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.