01 -
Preheat oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan.
02 -
In a saucepan, combine Coca Cola, vegetable oil, unsalted butter, and cocoa powder. Bring to a boil over medium heat while stirring occasionally.
03 -
In a large bowl, whisk together granulated sugar, all-purpose flour, miniature marshmallows, and salt.
04 -
Pour the hot Coca Cola mixture over the dry ingredients and stir until fully combined.
05 -
Add eggs, buttermilk, baking soda, and vanilla extract to the batter. Mix until smooth and homogeneous.
06 -
Transfer batter to the prepared pan and bake for 30 minutes, or until a toothpick inserted in the center comes out clean. Let cool slightly before frosting.