Preheat the oven to 350°F. Line baking sheets with parchment paper or silicone baking mats.

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

In a large bowl, cream together the softened butter, sugar, and brown sugar until light and fluffy, about 2 minutes.

Add eggs one at a time, mixing well after each addition. Stir in vanilla extract.

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

Gently fold in the diced apples.

Using a cookie scoop, portion the dough into 1.5 tablespoon balls, place on prepared baking sheets, and refrigerate for 20-30 minutes.

In a small bowl, combine 5 tbsp sugar with cinnamon and nutmeg. Roll chilled cookie dough balls in the mixture.

Arrange the coated dough balls on baking sheets with about 2 inches apart.

Bake for 10-12 minutes, until edges are golden and centers are set.

Allow cookies to cool on baking sheet for 2-3 minutes before transferring to a wire rack to cool completely.