Preheat your oven to 350°F (175°C) and line four 8-inch round cake pans with parchment paper, lightly spraying them with non-stick cooking spray.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking powder, baking soda, and salt until well combined.

In a separate bowl, combine the warm water, buttermilk, vegetable oil, eggs, and vanilla extract. Whisk these ingredients together until they are thoroughly incorporated and look smooth.

Gradually pour the dry ingredients into the wet mixture, gently folding with a spatula or whisk until just combined.

Divide the batter evenly among the prepared pans, filling each about two-thirds full. Bake for 22-25 minutes.

In a heavy-bottomed saucepan, gradually melt sugar over medium heat, stirring continuously until it turns a deep amber color. Carefully add in the unsalted butter and heavy cream, mixing until combined.

In a large mixing bowl, beat the room temperature unsalted butter and creamy peanut butter together until fluffy, then gradually add in powdered sugar and a splash of heavy cream.

Place one layer of chocolate cake on a serving plate and evenly spread a layer of peanut butter buttercream on top, followed by a drizzle of the peanut caramel. Repeat for each layer.

In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer. Pour over a bowl of chocolate chips and gently stir until smooth.

Once the ganache has cooled slightly, pour it over the top of the cake, drizzling any remaining peanut caramel over the top, followed by chopped mini Snickers bars.