Fortunately, I already had beets on hand, so I peeled and chopped a medium sized beet.
I just barely covered the chopped beet with water and boiled it uncovered, so the water would evaporate - until the beets were tender and there was about half the water in the pan that I started with.
I set this aside to cool, then drained off the liquid.
I probably used about 1/2 teaspoon of the beet juice in my icing to make it nice and pink.
There was plenty of the red beet liquid leftover, so I poured it onto a baking sheet lined with plastic wrap. This, I put into the freezer. After it was frozen, I broke it up into small bits about 1/2 teaspoon each and put it into a ziplock bag - so the next time I want to make pink icing - I will have it on hand and will not need to make it from scratch! I believe the beet liquid would gradually go brown in the refrigerator - so the freezer seemed like the way to go! I'll let you know the next time I use it!
Frozen concentrated beet liquid for use as natural food coloring