Measure one cup or more of granulated splenda and put it in your food processor or mixer. Using a granulated formulation will make sure your splenda binds well with the cornstarch or flour.
Add cornstarch to the mixer or food processor, one teaspoon for each cup of granulated splenda, that is if you are using three cups splenda, add three teaspoons full of cornstarch to the mixer or food processor.
Cover the processor and turn it on medium speed for one minute or until the splenda and cornstarch mix together completely. Make sure you stop the processor a couple of times during the process and mix the dry ingredients, as they may cling to the sides of the bowl. Scrape down the sides of the mixing bowl, before turning the processor on again.
Once you reach the desired texture, turn the food processor off and store the Low Calorie Powdered Sugar in a clean airtight jar.
You can use this powder to dust cakes, cupcakes etc, but it cannot be used for caramelizing food or for icing purposes.