What's the best way to make black royal icing?

Wilton black food coloring.
I just did it yesterday. Let it set about an hour if it looks too light. I'll be posting a photo soon of the cake I made.

I like to start by making the icing brown (and extra yummy) by adding some cocoa powder to it.

Then, I use americolor black food coloring. I use enough that it turns a dark gray. Then put the icing in a air-tight container and let it sit for several hours or overnight for the color to deepen.

Use Americolor super black