My wife had baked cupcakes with my daughter earlier in the day, but had me to help make the frosting for her cupcakes, and so we just did a simple butter cream frosting for her. She learned the importance of 'pulsing' the mixer when playing with powdered sugar, but not until we had a fine cloud of it spreading around the kitchen.
In the interest of 'victory', looks being as important as taste in competition like this, I finally broke down and ordered a piping bag/decorating kit off of Amazon. What a game changer. It is going to take a while to master the technique, but my daughter loved piping frosting on vs. trying to use a spatula.
In the end, I felt kind of bad for my daughter. She didn't win in her category. I will admit some of the other cupcakes looked, and tasted a bit better than hers, but to my eye, some kids had a LOT more help their parents. We supervised, and then, I helped fill the piping bag so there wasn't a huge mess...but heck, some of the 4th graders had fondant on theirs! What 4th grader plays with fondant without major parent help.
I did win the adult category, and got a sweet ribbon to prove it. I'll probably let my daughter put it in her room.