Prepare the topping by combining the sugar and cinnamon in a small bowl. Set it aside.
Cream the butter and sugar together using an electric mixer for 1-2 minutes until fluffy. Add the egg and vanilla extract, mixing well, then set the bowl aside.
In a separate bowl, whisk together the flour, cream of tartar, baking soda, cinnamon, and salt. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until fully combined.
Stir in the diced apples until evenly incorporated.
Using a cookie scoop, portion out the dough, then gently flatten each scoop with your fingers. Flatten one caramel slightly and place it in the center of the dough. Mold the dough around the caramel, then roll it into a ball.
Roll each dough ball in the cinnamon-sugar topping mixture until fully coated. Arrange the cookie dough balls on a greased baking sheet.
Bake at 350°F for 10-11 minutes or until the cookies are lightly golden brown. Let the cookies cool on the baking sheets for 15-20 minutes before transferring them to a wire rack to prevent them from falling apart. Alternatively, enjoy them warm with a spoon and a scoop of vanilla ice cream. 😉