Let’s walk through the process of making these delicious cookies. Remember, each step is a chance to create memories, so feel free to involve your little ones if you have them around!

1. Preheat your oven to 375°F (190°C) and line two baking sheets with parchment paper.
2. In a medium bowl, whisk together the flour, cream of tartar, baking soda, and salt. Set aside.
3. In a large bowl, cream the butter and sugar with an electric mixer until light and fluffy, about 3-4 minutes. This step is crucial for achieving that soft, chewy texture.
4. Add the eggs one at a time, beating well after each addition, then mix in the vanilla extract.
5. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
6. Gently fold in the diced apples, ensuring they are evenly distributed throughout the dough.
7. In a small bowl, combine the rolling sugar and cinnamon.
8. Using a cookie scoop or tablespoon, form the dough into balls, then roll each in the cinnamon-sugar mixture.
9. Place the dough balls on the prepared baking sheets, spacing them about 2 inches apart.
10. Bake for 10-12 minutes, or until the cookies are lightly golden around the edges. They will appear soft in the center but will firm up as they cool.
11. Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.