How much BC would you use to ice a 13 times 9 inch cake? I was going to make this recipe that would make about five-ish cups, but Gee! It sounds like SO much! I am going to need some black icing for this cake, so can I add some black coloring to make it black? Thanks.

http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

According to Wilton you need 6 cups to ice and decorate it.

If you are going to make black icing remember that the colors will darken over time so you may want to make the frosting in advance order to get a darker/truer black

Approximately 6 cups but I always make a little extra for the piping and such.

Before you add the black coloring, (not sure whether you are using gels or not,) but if you add a bit of chocolate (cocoa)powder with a touch of water and blend well, then add your black. It will make a black color instead of dark gray. Hope this helps! (This is what I do when I want real black not gray.)

Okay, thanks TexasSugar!

@Michel30014: I am using the Wilton Black.