Best bakery-style cupcakes

So for quite a while I've been looking for a good frosting recipe. And not just any frosting, but the kind the grocery store bakeries make... I know that in the world of frosting this kind isn't highly esteemed, but I really like it sometimes...ok a lot. Anyway, over the past few holidays I have experimented with different recipes and techniques and for mother's day I nailed it!
This time for the cupcakes I used a boxed mix. It suited the situation this time...
Frosting Recipe
1/2 cup butter, room temp
1/2 cup shortening
1 TBL corn syrup
1 tea vanilla
2+ cups powdered sugar (I used a third of a bag)
Beat (and I do mean beat) the butter and shortening using a paddle attachment (a whisk attachment will take forever) until the butter is no longer yellow, about one minute. Add in one cup powder sugar and mix to incorporate. Add the corn syrup and vanilla. Add another cup of the powdered sugar and once it incorporates beat it for two minutes. If you want a thicker frosting for piping and whatnot add more powdered sugar. If you just want it light and fluffy to spread on the cupcake then don't add more.
Tips: make the frosting in a cool kitchen. I did it about three hours after the cupcakes were made and it prevented the frosting from separating.