I just found this site and I'm excited to learn some things here. So Hello. Some context: I'm new to cake decorating. My mom tells me I have a knack for baking that only my great grandma could compare to and she was the best in the family. Yet, I don't know a thing about icings. I made my first cake for the public eye just this past weekend for my niece's 1 year birthday party. And it was bad. My mom asked for Royal Icing because she thought it was 7-Minute Frosting. So in the Texas humidity, it melted. Bad. And when it was taken indoors, it got a hard candy-like crunch to the frosting. So, now that I've done some research, my question is....Is there an alternative to Buttercream to pipe decorations on cakes and cupcakes that will hold shape, not get crunchy, and not melt altogether?I saw a post regarding 7-Minute frosting that states that it could melt off and is not ideal for more than 24 hours to sit. But my family doesn't like the weight or sweetness of Buttercream, so I'm looking for a less sweet, almost marshmallow fluffy alternative that will stand up to decorating and possibly cake leftovers.  Does such a thing exist? Any help and feedback for this newbie is greatly appreciated, I'm looking to redeem myself with a surprise redo for my niece. 

I've mostly made pies and cookies, no decorating required, so I have included pictures of my first endeavor and you can't really tell, but the mane in the back of the sad eyes that have fallen is all melted :(

First of all, Royal Icing, Buttercream, and 7-Minute Frosting are three entirely different types of frosting.  Royal is rarely used to frost the whole cake and yes, 7-Minute Frosting, while delicious, is too soft and unstable for piping.  American Buttercream is the easiest to master and the most stable in hot, humid weather, but a delicious, less sweet alternative is Swiss Meringue Buttercream.  It is a bit more tricky to master, but it not really hard to make.  Here is a great video, which includes the recipe, on how to make SMBC.

I have to commend you for your beautiful, flat top and straight sides!  That is harder to achieve than frosting, so you are making great progress!   Here is a short tutorial that you might enjoy.