Preparation Steps

• Preheat your oven to 375°F (190°C). Line a 15x10x1 inch baking sheet with parchment paper, allowing some overhang on the sides for easy removal.
• In a large bowl, using an electric mixer, beat the softened butter, granulated sugar, and light brown sugar until light and creamy. Scrape down the sides of the bowl as needed.
• Add the kosher salt, large eggs, and vanilla extract to the creamed mixture. Beat until well combined.
• In a separate bowl, whisk together the all-purpose flour, unsweetened cocoa powder, and baking soda. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Do not overmix.
• Fold in the crushed Oreos and red and green M&M's (or chocolate chips) into the cookie dough. The batter will be thick.
• Press the thick cookie dough evenly into the prepared 15x10x1 inch baking sheet. Bake for 15-20 minutes, or until the edges are set and the center is still slightly soft (it will continue to set as it cools). Remove from the oven.
• While the cookie bars are baking, prepare the white chocolate fudge topping. In a small saucepan over medium heat, combine the sweetened condensed milk and 2 tablespoons of unsalted butter. Stir constantly with a whisk until butter is melted and mixture is warm.
• Remove the saucepan from the heat and immediately add the Ghirardelli white chocolate wafers to the warm milk mixture. Stir continuously until the white chocolate is completely melted and the mixture is smooth and glossy (this should take about 2 minutes).
• Pour the warm white chocolate fudge over the still-warm baked cookie bars and spread evenly with an offset spatula. Immediately sprinkle generously with the crushed peppermint candy canes before the fudge sets.
• Allow the bars to cool completely and set at room temperature for about 30 minutes, or until the fudge is firm. Once set, lift the bars out of the pan using the parchment paper overhang, then cut into squares and enjoy!