For the cake:

1. Preheat the oven to 350°F. Grease and flour three 8-inch baking pans, lining the bottoms with parchment paper circles.
2. In your stand mixer, whisk together the dry ingredients: sugar, flour, cocoa powder, baking soda, and salt. Set aside.
3. In a separate medium-sized bowl, whisk the eggs together with the vanilla extract. Then add the buttermilk and vegetable oil, whisking all the wet ingredients together.
4. Next, pour the wet ingredients slowly into the dry ingredients while the mixer is beating at a low speed. Once all the wet ingredients have been added, increase the mixing speed to medium and mix until all the ingredients are combined, scraping down the bowl as needed.
5. Divide the cake batter evenly between the 3 baking pans. Bake at 350°F for 30-35 minutes or until the toothpick inserted into the center of the cake comes out clean. Remove the cakes from the oven and place them on a wire rack to cool for one hour. Gently run a knife on the inside edge of the pan to release the edges of the cake from the pan. Carefully remove the cake from the pan and allow it to cool completely.

For the chocolate crunch:

1. Line a 9×13-inch baking sheet with parchment paper and set aside. In a microwave-safe bowl, melt the chocolate in the microwave on medium-high power in 15-second increments, stirring between each interval until the chocolate is fully melted.
2. Place the Rice Krispie cereal in a medium-sized bowl and pour the melted chocolate over the cereal. Stir with a spatula until the cereal is well-coated.
3. Spread the cereal evenly on the baking pan and transfer to the refrigerator until the chocolate is set.

For the frosting:

1. In a microwave-safe bowl, melt the chocolate in the microwave on medium-high in 15-second increments, stirring between each interval until the chocolate is fully melted. Set aside and allow it to cool to room temperature.
2. In your stand mixer, beat the butter until completely smooth 2-3 minutes. Next, add the powdered sugar 2 cups at a time, beating until the powdered sugar is well mixed into the butter. As the frosting thickens, add the liquid ingredients (vanilla and heavy cream) 1 tablespoon at a time as needed. Beat the frosting until light and fluffy.
3. Slowly add the melted chocolate, mixing it into the buttercream until it’s well incorporated.

To assemble the cake:

1. Use a cake leveler to cut the domes off the top of the cake. Place a dollop of frosting on your cake board and place the bottom layer of cake on top of that.
2. Pipe a layer of frosting. I use a piping bag fitted with an open round tip, or simply cut off the end of the piping bag. Fill the first layer of frosting by using your piping bag and pipe from the outside edge into the center. Gently spread the frosting with an offset spatula to fill in the gaps.
3. Break apart the chocolate crunch into smaller pieces and press about 1/3 of the chocolate crunch into the layer of frosting, and spread a thin layer of frosting over top of the chocolate crunch.
4. Place the next layer of cake on top and repeat the above instructions to fill the layer of frosting and chocolate crunch. For the top layer of cake, place it inverted, so the bottom of the cake is actually the top, creating a nice and smooth top edge. Use the remaining frosting to coat the edges and the top of the cake.

For the ganache:

1. In a 1-cup capacity measuring cup, combine the chocolate chips and heavy whipping cream. Microwave at 50 percent powder for 30 seconds at a time, and stir after every 30 seconds. Repeat until the chocolate is melted and smooth then stir in the corn syrup. The chocolate ganache should run smoothly off your spoon. Pour the chocolate around the top edge of the cake and allow it to drizzle down the sides of the cake. Pour in a circular pattern on top of the cake.
2. Garnish the cake with any leftover chocolate crunch on the top and bottom edges of the cake.