When you run out of confectioners sugar..what to do?

I was trying to make  mint chocolate brownies and i thought i had enough confectioners sugar. I needed 2.5 cups and was short 1/2 cup. I flipped the house over searching for more confectioners sugar, but couldn't find any anywhere. I usually have tons of it hanging around, because i am always making cakes for someone. So, I searched the internet and was surprised to find out i could make it by using 2 ingredients. Want to know what they are? table sugar and cornstarch.So, for every cup of table sugar, use one teaspoon of cornstarch. To prevent it from clumping up, cornstarch has been added as an anti-caking agent. This article said to use a blender, not a food processor. I have a blender, but decided to use my nutribullet instead with the milling attachment for nuts. I put 1 cup of sugar and 1 t of cornstarch and put the bullet on for 10 seconds. I couldn't believe when i opened up the top there was powdered sugar. I was ecstatic. A lot of times when i try something from the internet that someone has posted it doesn't work, but this worked fabulously. So, I was able to continue on with making the brownies without having to stop and run to the store.