The powder sugar is much more dense and it is much too sweet for cookies, it is used mostly for icing because of its thickness. Powdered or confectioners’ sugar is granulated sugar that has been finely ground and mixed with a small amount of cornstarch to prevent caking. Powdered sugar has a teeny bit of cornstarch in it to keep it from clumping and that plus the powdery consistency of confectioners sugar keeps the cookies soft and tender. Then again, with heat and time, it can caramelize into something complex and deliciously bitter. So was it the butter or the combination of sugars? There are two main factors that keep these cookies soft for days: Powdered Sugar: instead of using granulated sugar, this recipe uses powdered. It refers to the number of times the sugar is processed and milled—in this case, 10! It is quicker to run to the store and pick up the sugar … Its best friend is salt, though most dessert recipes don't pair them as often as they should. Confectioners' sugar, on the other hand, is powdered sugar with starch added, to prevent it from caking as it sits. Doing some research , per America's Test Kitchen, granulated sugar adds crunch while confectioners sugar adds tenderness. They have an ice box cookie recipe that combined both and the taste was wonderful but it spreaded badly even though it states it would not. Granulated sugar is colorless, odorless, and neutral in flavor, allowing the flavors of other ingredients to come to the fore. The thing is that I melted the butter instead of letting it soften, and I just found out today that that's supposed to make a difference to the texture (even though I've done it before with sugar cookies without any problems). This is the sugar we commonly use for frostings, glazes, and that snowy covering on doughnuts that no doubt is all over your face and hands with the first bite. So using all confectioners sugar made the cookies too "soft". The first recipe I tried called for 1/2 cup powdered and 1/2 cup granulated and they came out kinda hard. Powdered sugar is simply granulated sugar that has been ground to a very fine powder. What About Powdered Sugar? Sometimes referred to as table or white sugar, granulated sugar is a highly refined cane or beet sugar (all of the naturally present molasses has been removed). When a recipe simply calls for "sugar," more than likely you need granulated sugar. Did you ever wonder what the "10x" on the label means? Fun fact: Powered sugar or confectioner’s sugar is just regular white sugar that has been pulverized to a fine, fluffy texture (so if you need powdered sugar and only have white granulated sugar at home, simply blitz it in the food processor or blender until it turns into the powdered stuff).