1. Preheat your oven to 350°F and line a baking sheet with parchment paper.
2. In a medium bowl, whisk together flour, baking soda, salt, and cream of tartar. Set aside.
3. In a large mixing bowl, beat butter and sugar until light and fluffy.
4. Add eggs, vanilla extract, and peppermint extract, mixing until well combined.
5. Gradually add the dry ingredients to the wet ingredients, stirring until a dough forms.
6. Cover the dough and chill it in the refrigerator for at least 30 minutes.
7. Once chilled, scoop out dough portions and roll them into small balls.
8. Place the dough balls on the prepared baking sheet, spacing them about 2 inches apart.
9. Bake in the preheated oven for 10-11 minutes, or until the edges are set but the centers remain soft.
10. Remove cookies from the oven and let them cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
11. In a microwave-safe bowl, melt white chocolate chips and shortening in 20-second intervals, stirring in between until smooth.
12. Dip each cooled cookie halfway into the melted white chocolate.
13. Immediately sprinkle crushed peppermint candy over the white chocolate before it hardens.
14. Place the dipped cookies on a parchment-lined surface to set.
15. Let the chocolate harden completely before storing or serving.
16. Store cookies in an airtight container at room temperature for freshness.
17. Enjoy your festive White Chocolate Dipped Peppermint Sugar Cookies or package them for gift-giving!