1) Preheat oven to 350 degrees.
2) Line a 13X9 baking sheet with parchment paper. If you don’t have any parchment paper, you can just spray the sheet with nonstick spray.
3) In a small bowl, whisk the flour and salt together and set it aside.
4) Add your butter to a mixing bowl and either mix it with a stand mixer or hand mixer until it’s creamy. Add sugar and beat it until it’s light and fluffy.
5) Add the vanilla and egg yolk and continue to beat. Remember to scrape down the sides of the bowl every once in awhile.
6) Spread out cookie dough onto the prepared baking sheet. Take a fork and stab it all around.
7) Bake this for about 25-30 minutes or until the cookie crust is slightly browned all over.
8) As soon as the gigantic cookie comes out of the oven, sprinkle the chocolate over the surface. Let this sit for about 5 minutes. The chocolate will slowly melt.
9) Unwrap a bunch of peppermint candies, put them in a plastic bag and give them a few whacks with a mallet or rolling pin. It’s okay if they are broken up kind of unevenly.
10) Spread melted chocolate out using a flat spatula or knife. Make sure the chocolate covers all the cookie crust. Then sprinkle your peppermint all over the surface.
11) Melt the white chocolate in the microwave (on low) or in a double boiler. Add a few tablespoons of water no matter how you do it to make sure that your chocolate sauce is smooth and liquidy. That just makes it easier to drizzle.
12) Once it’s melted, drizzle it over the surface of bark using a fork. Place in the fridge for at least a few hours to make sure everything is hardened.
13) Remove and break it up with your hands!