To make the cake, place the cola, dark brown sugar and cocoa powder into a medium sauce pot and mix to combined being careful not to fizz over the cola. Add the butter. Place over a medium heat and bring the mixture to a bubble, stirring occasionally, until the butter has melted and sugar has dissolved. Remove from heat to cool slightly.
While the mixture cools, in a large bowl, whisk together flour, baking soda and salt. Pour the slightly cooled but still a bit warm chocolate-cola mixture into the dry ingredients and whisk until smooth. Pour the batter into a large ungreased sheet pan or jelly roll pan. The pan should be about 12x16 (half-sheet pan size) but any similarly sized pan should do the trick.
Place the pan into the oven and bake for 15 minutes. Insert a toothpick into the middle to check for doneness. If the toothpick comes out clean, remove. If not, bake for 5 minutes more. Time may vary with the size of your pan. Remove from oven and let cool.
To make the frosting, mix together the peanut butter and butter in a stand mixer using the paddle attachment. Once well combined, slowly add in the confectioner’s sugar at a low speed. Once all of the sugar has been incorporated, carefully add in the salt, cream and vanilla extract. Once the ingredients have come together, turn the mixer on high and beat for 20 seconds just to incorporate a little air and to “fluff” the frosting.
Frost the cake. And garnish the top with peanuts.
Slice the cake and enjoy with a chilled bottle of Coca-Cola because, why not?
Grant Melton is an Emmy Award-Winning Producer of the Rachael Ray Show, food writer and recipe developer. He's a contributor to Food52, Food Network Kitchen and Rachael Ray Every Day Magazine. He loves cookies, cocktails and kindness.