Tips:
So with icing a cake (or cupcakes) you definitely need equipment, but that depends on what style you are going for…..

With a pattern or flower techniques, you will need a piping bag
Like this one. Basically, you just add your icing to your piping bag cut the narrow part and squeeze gently when the icing comes out and start piping in circular motions.
The other technique is where you don’t use a piping bag and you will only use a spoon. It’s much easier to do and a lot quicker. Basically, you get a blob on your spoon, then you dab it on the cupcake, smoothe it out and your finishing product should look like this (you can add sprinkles if you want).
