Preheat oven to 350˚. Spray a 13x9-inch baking dish with baking spray with flour.
In a large bowl, combine flour, sugar, baking soda, cinnamon, and salt.
In a medium saucepan, bring butter, cola, buttermilk, and cocoa to a boil over medium-high heat, whisking constantly. Remove from heat, and add to flour mixture, whisking until smooth. Add eggs and vanilla, whisking until smooth. Spoon batter into prepared pan.
Bake until a wooden pick inserted in center comes out clean, 30 to 35 minutes. Pour Cola Frosting over hot cake. Let cool for 30 minutes before serving.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/chocolate-cola-cake-recipe/