This consistency is a great starting point to simply store on your countertop in an air tight container. Why?
One....Because over time, your royal icing will have water separate and you will always be left with a simple starting point base that you can dilute down in smaller batches as needed.
Two....it works beautifully as glue for gingerbread houses and 3D cookies
Three....it is nearly the consistency you can use to make a thick, beautiful texture to pop off a cooke with your plastic stencils
So....first things first....mix your recipe according to the instructions HERE.
My preferred method with this consistency is to drop a spoonful of your thick consistency onto a plate, and use a spatula to add in your color. The goal with this icing is to keep it really thick.