Start by preheating your oven to 350°F so it's ready when you need it. While the oven heats, chop the white chocolate peppermint bark into small pieces using a knife or food processor, then crush the peppermint candies into uniform pieces using a food processor—this ensures even distribution and a consistent texture throughout your cookies. Pour the crushed candies into a shallow bowl for easy dipping later.

In a large bowl, combine the softened butter, coconut oil, and eggs, mixing until well combined. Add the devil's food cake mix and stir until the mixture comes together into a cohesive dough—the cake mix acts as both a dry ingredient and flavor base, making this much simpler than a traditional cookie. The dough will be slightly thick and fudgy, which is exactly what you want.

Gently fold the chopped white chocolate peppermint bark into the dough from Step 2, distributing it evenly throughout. I like to reserve a few of the larger pieces to press into the tops of the cookies later for extra visual appeal. Let the dough rest for 10 to 15 minutes at room temperature—this allows the chocolate to soften slightly and helps the cookies bake more evenly.

Scoop the dough into balls roughly the size of a tablespoon and dip the top of each ball into the bowl of crushed peppermint candies from Step 1, pressing gently so the candies adhere. This creates a festive, candy-coated top that will provide a nice texture contrast. Place the coated dough balls on a baking sheet lined with parchment paper, spacing them about 2 inches apart, and press down slightly so they're slightly flattened.

Bake the cookies in your preheated 350°F oven for 4 minutes until the tops begin to set but still look slightly shiny. Remove the pan from the oven and tap it firmly on the counter a few times—this causes the cookies to settle and creates those signature crackled tops that peppermint bark cookies are known for. Return to the oven and bake for 3 to 4 more minutes until the cookies lose their shiny appearance and the edges are set but the centers are still slightly soft.

Let the cookies cool on the baking sheet for 5 to 10 minutes—I find this time crucial because it allows them to set without becoming brittle, keeping the centers fudgy and the candy coating intact. Transfer the cookies to a wire cooling rack to cool completely, which should take another 10 to 15 minutes. The cookies will continue to firm up as they cool, developing that perfect chewy-fudgy texture.