So I was making chocolate buttercream for a cake due tomorrow and I think I made a big boo-boo.  I think I put an extra cup of buttercream in my recipe somehow.  The icing tastes fabulous and is a great consistency (my mom says she would never have known had I not said something), but I worry how this would affect covering the cake in fondant.  I was in the middle of smoothing it on the cake before I realized what I'd done.  Do I need to scrape it all off and start over?  Here is what I used:

1 cup salted butter

1 cup (actually two, oops!) shortening

6 oz melted semi-sweet chocolate chips

2 tsp vanilla

2 lbs powdered sugar

4 tbsp water

I was having to fight off my 22-month-old the entire time I was making this icing, so that is how I messed up and got started icing my cake before I noticed my blunder.  AAAAHHHH!!  I really didn't want to start the day like this.

It should be okay. It might be a little softer than usual but there are so many recipes with varying amounts of fat it's not a huge deal. Unless the cake is going to be somewhere really hot it shouldn't matter.

Or you could double up on the rest of the ingredients as well to make a double batch and freeze the excess.  It will give you a leg up next time you need chocolate icing.

I wouldn't worry. My buttercream recipe is a chunk of butter about half that much shortening, enough icing sugar to make it look good and a slosh of milk. It always works.

Thanks, guys.  I wound up freaking myself out because it wasn't hardening in the refrigerator and just scraping off as much as I could and adding what would make a full recipe and it tasted soooo much better.  The oops was left as the filling, but the client didn't notice the difference.  If I had the picture on my computer I would post it.

softer than usual