Chocolate Coca Cola Cake

I can still remember my Mum pouring out a bottle of Coke to make this cake, it was our favourite. This cake is so moist and the icing is just irresistible.

1 cup Coca Cola
½ cup extra-virgin oil
1 stick butter
3 Tbsp. cocoa
2 cups sugar
2 cups all-purpose flour, unbleached
½ tsp. kosher salt
2 eggs
½ cup buttermilk
1 tsp. baking soda
1 tsp. pure vanilla extract

Frosting:
1 stick butter
3 Tbsp. cocoa
6 Tbsp. cream or milk
1 tsp. pure vanilla extract
3¾ cups confectioners' sugar

Preheat oven to at 350°F (180°C/160°C fan, Gas Mark 4). Grease and flour a 13x9" baking pan.

In a saucepan, mix Coca Cola, oil, butter and cocoa and bring to a boil. In another bowl, combine the sugar, flour and salt. Pour the boiling Cola mixture over the flour mixture and beat well. Add the eggs, buttermilk, soda and vanilla and beat well. Pour mixture into a prepared baking pan and bake for 20-25 minutes. Remove pan. Cool for about 10 minutes before frosting.

For the Frosting:
In a saucepan, combine the butter, cocoa, and milk. Heat until the butter melts. Beat in the remaining ingredients and spread on the cake while it's still warm.