A sweet and tangy coating for candy, sour powdered sugar is not accessible to many consumers. With some readily available ingredients, you can make your own for lining drink glasses and topping for cookies and candies. This recipe requires powdered citric acid -- also known as sour salt -- which is a naturally derived from the peel of citrus fruits. Look for it with Kosher foods or baking ingredients at well-stocked grocery stores.
Add the powdered sugar and citric acid to a resealable plastic bag.
Seal the bag and shake it to combine the ingredients.
Add warm cookies or candies to the bag with the sour powdered sugar. Close the bag and toss the items to coat them.
Discard any leftovers.