Step 1

Preheat the oven to 350 degrees F. Spray three 8-inch or four 6-inch round cake pans with nonstick spray. Line the bottom of each pan with parchment paper, then spray the parchment paper. Set aside.

Step 2

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.

Step 3

In another bowl, combine the buttermilk, oil, eggs, water (or coffee) and vanilla. Whisk until combined.

Step 4

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

Step 5

Evenly divide the batter into each of the three pans (about 15 to 16 ounces of batter in each 8-inch or 12 ounces in each 6-inch). Bake for 16 to 18 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs on it.

Step 6

Cool in the pans for 10 minutes, then turn them out onto a cooling rack and cool completely. (I like to spray my cooling racks with nonstick spray to ensure non of the cake sticks to the racks).

Step 7

If needed, level your cake layers to ensure a completely even surface for frosting and stacking. After leveling you can wrap each cake layer in plastic wrap and freeze until ready to use.

Step 8

Heat the cream in a microwave safe bowl for about one to two minutes. Pour the heated cream over the chocolate chips in a medium sized bowl. Let sit for about five minutes.

Step 9

Stir the chocolate and cream until nice and smooth. Add the marshmallows, peanuts and toffee bits and stir until combined.

Step 10

Let the filling cool completely before using.

Step 11

In a bowl fitted with a paddle attachment, beat the butter on medium speed for about two minutes.

Step 12

Slowly add the melted, cooled chocolate and beat on medium speed until smooth. Scrape down the sides of the bowl and mix for another 30 seconds.

Step 13

With the mixer on low speed, gradually add the powdered sugar and mix until combined.

Step 14

Add the vanilla, salt and heavy cream. Turn the mixer to medium-high and beat the frosting for another 3-4 minutes until light and fluffy.

Step 15

Before frosting your cake, use a wooden spoon to hand mix the frosting to push out air bubbles.

Step 16

Heat the cream in a microwave safe bowl for about one minute. Pour the heated cream over the chocolate chips in a medium sized bowl. Let sit for about five minutes.

Step 17

Stir the chocolate and cream until nice and smooth. Let cool before using on the cake.

Step 18

Place the first cake layer on a cake board or cake plate.

Step 19

Pipe a rim of frosting around the cake layer before adding the filling. This creates a nice barrier so the filling stays in place.

Step 20

Spread half of the filling within the frosting barrier.

Step 21

Place the second cake layer on top and repeat steps 2 and 3.

Step 22

Place your final cake layer, bottom side up, on top of the cake. Crumb coat your cake with a light coat of frosting. Freeze for about 10 minutes to set the crumb coat.

Step 23

Continue to frost the cake with the remainder of the chocolate frosting, saving about one cup of frosting for piping.

Step 24

At this point, I like to freeze the cake for another 10 minutes before I do the drip. After you do the drip, use extra extra frosting, peanuts, toffee and marshmallows to decorate the cake.