I know for dark frosting you need to make it ahead of time because it will get darker, but should I start with chocolate buttercream? Will I be able to get it black?

I always make chocolate first and then add the black color.

Thanks, I'm not working on the cake for a couple days but wanted to give it time to darken

If you use Americolors Super Black, you just add it to dark chocolate buttercream and it will be black in a few minutes. Americolors is wonderful for quickly achieving dark colors without a nasty bitter taste.

You can also mix together some leftover colors from other projects. You'll get a yucky green color. Then you won't have to add all that much black. I've done this a few times myself. It is also a good way to use up leftover colors.

Another CCer uses Duncan Hines dark chocolate fudge frosting for black.

The very vest thing I have ever found is the Ateco professional gel paste in a big plastic jar. You have to have a business account to get it. One Jar lasts over a year. It colors over everything!

I actually buy my black icing from Sam's club. It is the only way I have been able to have true black. I think I pay about $10 for a gallon bucket.