Prepare cake in a 9x13-inch pan according to package instructions, BUT replace water with an equal amount of Coca Cola.
While the cake is still warm, prepare the Coca Cola Frosting.
To prepare the frosting:
In a large saucepan, bring butter, cocoa powder, and Coca Cola to a boil, whisking regularly.
Remove from heat and mix in powdered sugar and vanilla until smooth.
Fold in the pecans and pour the hot icing over the warm cake. The icing will harden into a sweet shell over the cake as it cools.
Notes
How to store Coca Cola Cake:Cover the cake with plastic or foil and store at room temperature for up to 5 days.Does Coca Cola Cake need to be refrigerated?No, this cake does not need to be refrigerated.Can Coca Cola Cake be frozen?Yes! Wrapped tightly, the cake will last in the freezer for up to 2 months.COOK'S TIPS:
Check your package of chocolate cake mix to make sure that you're using the correct ingredients, since every brand differs slightly.
Make sure that you pour the Coca Cola Frosting over a warm cake.
Allow plenty of time for the cake to cool completely and the icing to harden before slicing and serving.