This Double Fudge Coca Cola Cake tastes even better than the one at Cracker Barrel and is easy to make since it starts with a boxed cake mix!
If you are using milk instead of heavy cream, you will probably only need about 3-4 tbsp. of it because milk is thinner than heavy cream. Just use your judgement on it. Start with less and add a little at a time to get the right consistency. Or, you can always add a bit more powdered sugar to the frosting to make it thicker if you like.