Hi...I have a quick question, I need to make black royal icing; besides adding alot of black gel paste. Can you add cocoa powder to make the icing darker without ruining the icing? (I still need it to harden) Thank you

If you have Americolor, it just takes a drop. Very concentrated and leaves no bitter taste. Don't know about the cocoa powder.

ALL DEPENDS HOW ARE YOU MAKING THE ROYAL ICING
DO YOU USE BUTTER OR SHORTENING?
I PUT LITTLE BY LITTLE AND LET IT SIT FOR A LITTLE BIT AND THE BLACK WILL COME UP...IT WILL GET DARK FIRST TURNS LITTLE GREY-ISH BUT AFTER YOU LET IT SIT FOR A BIT MIX AGAING ....IF YOU PUT COCOA IT GOING TO DRY IT AND IT WILL DRASTICALLY CHANGE THE TASTE...
I HAVE GOOD RESULTS

Sugarflair's Extra Black is great too... it works just fine for me... and the royal icing hardens normally.

Thank you all for your help and information. I'll try adding a little black at a time and let it sit