Blend 1 cup granulated sugar with 1 tablespoon cornstarch in a food processor or blender until fine and powdery. Use it cup for cup in frostings and glazes.
Ratios from university extension services and King Arthur Baking. Checked .
Powdered sugar substitutes, best first
- For 1 cup powdered sugar1 cup granulated sugar + 1 Tbsp cornstarch, blended in a food processor or blender until powderyBest for: frostings, glazes, dusting
Nebraska and UC Cooperative Extension.
- For 1 cup powdered sugar1/2 cup + 1 1/2 Tbsp granulated sugar + 3/4 tsp cornstarch, finely groundBest for: smaller batches
Iowa State AnswerLine; uses a small food processor.
- For 1 cup powdered sugar3/4 cup granulated sugarBest for: sweetening uncooked foods only
Colorado State; texture won't be smooth.
What not to use
Unground granulated sugar in frosting or glaze: it won't dissolve into a smooth finish.
Why the swaps work
Powdered sugar is finely ground sugar mixed with a little cornstarch to keep it from clumping; the fine grind lets it dissolve quickly in uncooked mixtures.
Questions people ask
Can I make powdered sugar without cornstarch?
You can grind plain sugar, but the charts' recipes include cornstarch to keep it from caking.
Can I use granulated sugar in frosting?
Not unless you grind it first; it stays gritty.
Can I use regular sugar instead of powdered sugar?
Blend 1 cup granulated sugar with 1 tablespoon cornstarch in a food processor or blender until fine and powdery. Use it cup for cup in frostings and glazes.