Ingredients
Method
- Heat oven to 350°F (175°C) and grease a 9x13-inch pan. In a medium saucepan over medium heat, melt the 1/2 cup butter with 1/2 cup vegetable oil, 3 tbsp cocoa powder, and 1 cup Coca-Cola until just bubbling, about 4 to 5 minutes. Remove from heat and stir in the 1 1/2 cups mini marshmallows until mostly melted.
- Whisk the 2 cups flour, 2 cups sugar, 1 tsp baking soda, and 1/2 tsp salt together in a large bowl.
- Pour the warm cocoa mixture into the dry ingredients and stir to combine. Add the 1/2 cup buttermilk, 2 eggs, and 1 tsp vanilla extract and stir until smooth with no dry streaks.
- Pour batter into the prepared pan and bake at 350°F (175°C) for 30 to 35 minutes, until a toothpick in the center comes out with just a few moist crumbs.
- About 5 minutes before the cake is done, melt the 1/2 cup butter with 3 tbsp cocoa powder and 6 tbsp Coca-Cola in a saucepan over medium heat, about 3 minutes. Off the heat, whisk in 3 1/2 cups sifted powdered sugar, 1 tsp vanilla extract, and 1 cup chopped pecans until smooth.
- Immediately pour the warm frosting over the hot cake, spread to the edges, let sit 15 minutes, then slice into squares and serve warm.
Notes
This cake is meant to be frosted hot, straight out of the oven. If you wait too long, the frosting sits on top rather than soaking into the surface slightly, and you lose that fudgy top layer. Make the frosting during the last few minutes of baking so everything is ready at the same time. Leftovers are genuinely good the next day once the frosting firms up overnight.
