Preheat oven to 350°F and prepare a baking sheet with parchment paper or non-stick silicone baking mat.
In a large mixing bowl, combine the flour, baking soda, salt and cream of tartar. Whisk together until well combined. Set aside.
In a separate bowl, combine the sugar and butter and mix (using a hand mixer or stand mixer) until creamy.
Add in egg, egg yolk, vanilla and peppermint extract to stand mixer bowl and continue mixing.
Gradually add bowl of dry ingredients to bowl of batter. As you mix, scrape the sides of the bowl to ensure that all ingredients are incorporated into the batter.
Use a cookie scoop to portion dough onto the cookie sheet and bake at 350°F for 8-10 minutes. Cookies will be slightly under-baked.
While cookies cool, melt the white chocolate using a double boiler.
Dip half of each cookie into the melted white chocolate and set back on the cookie sheet to dry.
Once all cookies are dipped, sprinkle with crushed candy canes.
Let cookies dry fully, then enjoy!
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Notes
Note: Nutrition information is a rough estimate only; actual values will vary based on the exact ingredients used and amount of recipe prepared.