Homemade Powdered Sugar

I know I have tried to make powdered sugar before and thought it was as simple as blending regular granulated sugar and that was it. It didn't quite come out right and maybe if I had the following tip about adding the Cornstarch (even though it says optional) it would have come out right.  Please let me know if you have tried it using CS and how it came out.

courtesy of Homemade Mamas

What You Need:

• 1 Cup Sugar
• Blender or Food Processor
• 2 Tbsp. Cornstarch (optional)

In your blender or food processor, add the sugar and cornstarch (if using it). Supposedly commercial powdered sugar has cornstarch in it to help prevent it from clumping.Blend it up for about 30 seconds or so. Check on it and blending more if needed.

That's it!