Preheat the oven to 350°F.

Whisk together the melted butter, brown sugar, granulated sugar, and peppermint extract.

Add in the eggs one at a time and whisk each one until fully incorporated and the batter starts to get lighter in color.

Fold in the cocoa powder, flour, and salt and mix until the batter is just combined.

Then gently fold in the chocolate chunks if desired.

Cut a parchment paper sling slightly smaller than the width of the cake pan and make sure it fits flatly in the bottom. Then lightly spray the bottom and sides of the pan with a vegetable oil based spray.

Place your parchment paper sling in the bottom of the pan and smooth it out so that it sticks to the pan spray.

Pour the batter into your prepared baking pan.

Bake at 350°F for 30-40 minutes or until an inserted knife comes out mostly clean.

Remove from the oven and let fully cool in the pan.

Add the chopped white chocolate and 1 ½ teaspoons of coconut oil to a microwave safe bowl. Melt in intervals of 20 seconds and stir in between each interval until fully melted and smooth. Stir in ¼ teaspoon of peppermint extract if desired.

In a separate microwave safe bowl, add the chopped dark chocolate and ¼ teaspoon of coconut oil. Melt in intervals of 20 seconds and stir in between each interval until fully melted and smooth.

While the peppermint brownies are still in the pan, pour the melted white chocolate over the top and smooth into an even layer.

Transfer the melted dark chocolate to a piping bag (or a plastic sandwich bag) and cut a small hole in the tip. Then pipe stripes of melted dark chocolate over the white chocolate layer. Then using a butter knife or skewer, create fun swirls in the top of chocolate!

Generously sprinkle the top with crushed peppermint pieces. Then place the brownies in the fridge for at least 20 minutes to let the peppermint bark layer firm up.

Once the chocolate has hardened, use the edges of the parchment paper to slide the brownies out of the pan.

Slice the brownies while still cold for nice clean cuts, but enjoy the peppermint bark brownies at room temperature for the best fudgy texture!