In a mixing bowl, combine 1 ½ cups flour, ⅔ cup cocoa powder, 1 teaspoon baking soda, and ¼ teaspoon salt. Whisk to combine fully and set aside. Place the 4 unwrapped candy canes in a small zipper lock bag without sealing and using a meat mallet or rolling pin, gently crush them. They shatter like glass, so use gentle pressure and try not to turn them into 100% powder.

In a large mixing bowl with a hand mixer, or in the bowl of a stand mixer with the paddle attachment, cream together the 12 tablespoons unsalted butter, ¼ cup granulated sugar, and ¾ cup brown sugar until light and fluffy, about 2-3 minutes. Add the ½ teaspoon vanilla extract and 1 teaspoon peppermint extract and mix on medium speed until combined, about 10 seconds. Add the egg and egg yolk, one at a time, and mix on low until fully combined, about 1 minute.

Combine the dry ingredients into the wet ingredients in 2-3 increments and mix on low speed until the cookie dough just comes together. Now fold in the 1 cup mini chocolate chips, and then fold in the crushed candy canes. Once everything is combined, refrigerate the cookie dough for about 2 hours or overnight.

Remove the cookie dough from the refrigerator and preheat your oven to 350°F/177°C. Line a baking sheet with parchment paper or a silicone baking mat.

Set aside two bowls, one with a ½ cup of white granulated sugar and the other with 1 cup of powdered sugar. Scoop out the cookie dough with a 1 ½ tablespoon cookie scoop or try to estimate that amount. Roll the cookie dough into a ball and then lightly coat it in the sugar, then heavily cover it with the powdered sugar. Place the dough on your baking sheet about 2-3 inches apart.

Bake the cookies for 9-11 minutes, mine usually took right about 10 minutes. The cookies should just be starting to set around the edges and the tops will form cracks. Let them cool for at least 5 minutes on the cookie sheet and then move to a cooling rack.

The cookies will keep covered at room temperature for about a week.