1. Preheat the oven to 350°F and line two baking sheets with parchment paper.

2. In a large bowl, beat the softened butter, brown sugar, and granulated sugar until creamy and fluffy.

3. Add the egg, vanilla extract, and peppermint extract, then mix until smooth.

4. In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.

5. Add the dry ingredients to the wet ingredients and mix just until a soft cookie dough forms.

6. Fold in the white chocolate chips and crushed peppermint candy.

7. Scoop the dough into 1 1/2-tablespoon balls and place them 2 inches apart on the prepared baking sheets.

8. Bake for 9 to 11 minutes, until the edges are set and the centers still look slightly soft.

9. Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.