Powdered sugar is the main ingredient of the icing recipe used as the base for dark blue icing. The recipe is adapted from C&H Sugar's basic buttercream frosting. Light colored frosting accepts food color readily. Any white icing, even ready to spread icing from the store, could be used as the base for dark blue icing. Dark blue icing is suitable for frosting cakes, making layer cakes, frosting cupcakes and decorating cookies. There is no cooking involved so children can help.
Dark Blue Icing
Allow the butter to soften. Using the bottom of the spoon, cream the powdered sugar and butter, using back and forth motions.
Add the vanilla to the butter and powdered sugar mixture. Add most of the water and mix until smooth. The frosting should be a spreadable consistency and not watery.
Add 5 drops of food coloring to the mixture and stir. Evaluate the color. If the frosting is not dark enough, add another 5 drops, mix and evaluate. It may take up to 24 drops to achieve a satisfactory dark blue color.
Check the consistency of the icing. It should spread easily, but stay in place on the cake or cupcake. If the icing is too watery, add powdered sugar a teaspoonful at a time to thicken it.