Preheat your oven to 375 degrees F. Spray three 8-inch round cake pans with non-stick spray and then line with parchment. Spray again. Set aside.

In a medium sized bowl combine the cookie crumbs and melted butter. Stir until all the cookie crumbs are damped by the melted butter.

Divide evenly between the three pans and press down firmly with your hand or the back of a spoon. (About 5.5 oz)

Bake for 7 minutes. Let cool while you make the chocolate cake batter.

Preheat the oven to 325 degrees F.

Combine the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined.

In another bowl, combine the buttermilk, oil, eggs, water and vanilla.

With the mixer on low speed, slowly add the wet ingredients to the dry, scraping the bottom of the bowl with a rubber spatula.

Pour the batter into the pans on top of the cookie crust (about 15-16 ounces in each 8-inch pan), and bake for 40 to 45 minutes, or until a toothpick inserted in the center of the cake comes out with a few moist crumbs on it.

Cool in the pans for 10 minutes, then turn them out onto a cooling rack and cool completely.

Wrap in plastic wrap and chill until ready to use.

Preheat the oven to 300°F–350°F.

Line a baking sheet with parchment paper or a silicone baking mat.

Pour the flour into an even layer on the baking sheet.

Bake for 5–12 minutes, or until the flour reaches a temperature of at least 160°F. You can use an instant-read thermometer to check the temperature in a few different spots. Stir the flour once or twice during baking to help break it up.

Let cool before using in the cookie dough.

Combine the butter, peanut butter, and sugars in a bowl of a stand mixer fitted with a paddle attachment. Beat for about 2 minutes–or until the mixture is light and fluffy. Next, add the vanilla extract and mix until combined.

Mix sugar, water and corn syrup in a small saucepan

Bring the water and sugar mixture to boil over medium heat, but DO NOT STIR. (Stirring encourages crystallization). Let the mixture cook until it caramelizes into a golden brown color (as seen in the photo above). It happens quickly, so keep an eye on it.

Remove the caramelized sugar syrup from the heat and slowly mix in the cream. Pour in just a tiny bit at a time, especially at the beginning, and mix to combine. You can start adding more and more as you go along.

Mix in salt and vanilla. Stir to combine.

Place the first cake layer, crust side down, in the middle of your cake board or cake plate.

Divide the cookie dough into two portions. Form an 8-inch cookie dough round on a parchment paper. Place the layer of the cookie dough on top of the cake layer. Drizzle with salted caramel.

Repeat these steps with the next layer of cake, cookie dough, and caramel.

Place the final cake layer, crust side down, on the second layer of cookie dough and caramel

Apply a thin coat of frosting around the entire cake to lock in the crumbs. Freeze for about 10 to 15 minutes.

After the crumb coat is set, continue frosting and decorating the cake with remaining buttercream.