Preheat your grill to 350°F. this recipe will use the indirect method.
Prepare two 9-inch cake pans by brushing them with butter and then sprinkling in cocoa powder and coating the butter. Alternatively, use nonstick spray, and then place a piece of parchment on the bottom of each pan and hit them again with a little spray. Set aside.
Sift together the flour, sugar, cocoa, baking soda, baking powder, and salt. In a separate bowl, whisk together the eggs, water, espresso powder, buttermilk, coconut oil, and vanilla.
Using a stand or hand mixer, slowly pour the eggs mixture into the flour mixture and combine. Once combined, turn the mixer onto medium-high and mix for 2 minutes. At this point, fold in the optional chocolate chips or Reeses pieces.
Divide the batter evenly between the two prepared cake pans and drop the pans from about 1-inch above the counter a couple of times. This will break any air bubbles in the cake to help prevent the cake from breaking when you take them out of the pan. Bake using indirect heat for 35 minutes, rotating the cakes half way through the bake. When a toothpick comes out clean remove them from the grill and allow the cakes to cool to room temperature on a rack before turning them out. Then move the cakes to the fridge, or freezer to cool further while you make the icing and ganache.
For the icing, Use a hand mixer to combine the peanut butter, butter, and cream cheese until fluffy. Add the smoked cream, vanilla, and powdered sugar. Continue to beat until fluffy. When the cakes are ice cold, if not frozen, divide the icing in half. Place the bottom layer of the cake onto a cake plate. Spread half of the icing on top of the first layer of cake. Repeat with the second layer of cake. Place in the fridge to set.
For the ganache, place the chopped chocolate into a heatproof bowl. Pour the smoked cream and butter into a saucepan and heat until the cream begins to steam. Pour the steaming cream over the chocolate and let it sit for 5 minutes. Whisk until the chocolate is completely melted and glossy.
Pour the ganache over the top of the iced cake, allowing it to drip however it wants. Top the cake with chopped peanut butter cups and Reeses pieces.
Serve to the delight of your friends, family, the birthday person, peanut butter enthusiasts, and chocoholics.