Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, cream together butter, brown sugar, and granulated sugar until light and fluffy.
Add eggs one at a time, beating well after each addition. Stir in vanilla.
In a separate bowl, whisk together flour, baking soda, cream of tartar, salt, and cinnamon.
Gradually add dry ingredients to the wet mixture, mixing until just combined.
Fold in chopped apples and white chocolate chips if using.
In a small bowl, mix 1/4 cup granulated sugar with 2 teaspoons cinnamon.
Scoop dough into balls and roll each ball in the cinnamon-sugar mixture.
Place dough balls 2 inches apart on prepared baking sheets.
Bake for 10–12 minutes or until edges are set and tops are slightly cracked.
Cool on baking sheets for 5 minutes before transferring to a wire rack to cool completely.