Powdered sugar
Sweetener
Powdered sugar — also called confectioners' or icing sugar — is ordinary white sugar ground to an extremely fine, flour-like powder and blended with a little starch to keep it free-flowing. It dissolves almost instantly, dusts as a soft white veil, and whips smoothly into icings and glazes, which is why it is the backbone of buttercream, royal icing, glaze and the snowfall over doughnuts and beignets rather than a sugar you would cream into batter.
Picking a good onedrag
Talc-fine, dry, sifts like smokeCaked solid, damp, set glassy
Open and free-runningEveryday bestThe working bag: glazes, fondant, marshmallow and cream-cheese frosting. A dusting sinking into a moist or chilled cake is normal - only "non-melting" survives that.
Put a spoonful through a sieveStill sifts freely, with a few soft pillows of powder that collapse at a touch of the spoon
Look at the powder itselfThe same white dust, only pressed close where the bag has settled on its own weight
The bag and the labelSealed and full, or tipped into a jar whose lid truly shuts, still moving freely