I saw this microwave royal icing coral technique a while ago and decided to try it to see if it was something that I could use on a recent cake.
To make this microwave royal icing coral, you’ll need royal icing that’s made with egg whites instead of meringue powder if possible.
You’ll be heating the icing in the microwave until it puffs up, then cooling it on a tray with a non-stick liner.
This makes large pieces of porous-looking sugar that looks like big chunks of coral. You can color it after it dries, or just add some food color before you heat it.
How to make the coral.
Remember that you’re working with hot sugar during this process, so even if it looks harmless this can burn you! This isn’t a good activity for kids!
Grease a pyrex bowl (I used nonstick cooking spray) and put about 1/2 cup of Royal Icing into it. Heat it in the microwave for 1 minute. It will puff up and look like a rocky surface.
Check the icing to make sure it doesn’t look like it’s burning. In the picture of the white you can see that there’s a spot in the center that seems to be getting darker. If that happens don’t heat it anymore.
If it’s not too hot, heat it for another 20 seconds or so.
Take the bowl out of the microwave, or leave it in the microwave with the door open and let it set. The bowl will be hot, so be careful. DO NOT try to stir the icing or remove it from the bowl yet.
Let the sugar set up and cool off completely, then take a spatula or a knife and slide it around the side of the bowl to release the sugar. It will probably break into pieces.
Break the sugar into pieces.
Once it cools completely you can break off irregular pieces to the size that you need and use them on the cake.
To color the coral, brush on powders, then either leave it or dip it in confectioner’s glaze.
If you dip it you should leave it to dry and not touch it for a while because it will be sticky and collapse on itself if it’s handled too much.
It will shrink a little naturally, so start with a slightly larger piece than you want to end up with.
Another type that’s easy to make using royal icing is the kind that looks like clusters of little fingers.
First, cook some of the royal icing in the microwave as described before.
When it cools down, crush it into small chips.
The next step is messy…Take some stiff royal icing, roll it out using your hands (the icing should be pretty stiff but still a little sticky) and roll it in the crushed chips.
When it’s totally covered, set them aside to dry.
Once all of the “fingers” have dried, dust them with some color if they were white and you want color, or leave them white.
Using melted sugar, royal icing or melted chocolate, attach as many of the pieces together at the base as needed to get the size coral cluster you want.
Another way to do the stick-shaped coral is to roll a long piece of fondant or gumpaste, wet it until it’s slightly sticky, then roll it in colored cake sprinkles.
Set them out to dry, and then dip them in confectioner’s glaze to set the sprinkles in place.
I’ve also seen the method of taking grape stems and piping royal icing over them to mimic the organic shape of coral using the stems.
That’s a good way to get the shape, but it won’t be totally edible.