I was hunting for a black icing that also tasted good. I found a dark chocolate buttercream icing recipe on the Wilton website, and I also discovered that King Arthur makes a black cocoa (it’s much darker than the Hershey’s Special Dark cocoa). You might have to hunt the cake shops to find it, or you can order at http://www.kingarthurflour.com/shop/items/black-cocoa-16-oz
I suppose if you want a super dark chocolate icing that’s NOT black, you can just omit the black food color. But if you do want it black, you need to make it a day in advance for the color to deepen (as with all deep colored icings).
Black Chocolate Icing
1 cup shortening
1 teaspoon vanilla extract
1/2 teaspoon butter flavor
1/2 cup unsweetened cocoa powder
1/4 cup black cocoa (King Arthur–see notes below)
4 cups (1 lb) confectioner’s sugar
4-5 Tbsp milk
black powder food color
Cream together the shortening, flavors, and cocoas, scraping down the sides of the bowl often. Gradually add sugar about a cup at a time, beating well on medium speed. Continue to scrape sides of bowl. When sugar has all been mixed in, the icing will be very dry, resembling oreo crumbs. Add milk and beat at medium speed until light and fluffy. Add in some black powdered food color (I think about 1-2 Tbsp should do the trick, but it won’t deepen to a true black for 24 hours). Store in an airtight refrigerator several hours or overnight. When ready to use, bring to room temperature and re blend just before using. Keep covered with a damp cloth or cling wrap while icing your cake.
***OPTIONAL: Add 3-4 tablespoons light corn syrup per recipe to thin icing, if desired.
***NOTE: If adding more black cocoa, do so very gradually as it is very deep and intense.