The-Real-Thing Sheet Cake - Hey Recipe

Ingredients

• 2 cups granulated sugar
• 2 cups all-purpose flour
• 1/2 cup unsalted butter
• 1/2 cup canola or vegetable oil
• 1/4 cup unsweetened natural cocoa powder
• 1 (12-ounce) can regular cola
• 1 teaspoon baking soda
• 1/2 cup buttermilk
• 2 large eggs
• 1 teaspoon vanilla extract
• 4 cups confectioners' sugar (sifted)
• 1 (12-ounce) can regular cola (plus more, to taste)
• 1/2 cup unsalted butter (cubed)