Arrowroot Powder (Best Option)
1:1 (use equal amount as cornstarch)Arrowroot powder is a fine starch extracted from tropical roots, known for its neutral flavor and excellent thickening properties at low temperatures. It gelatinizes quickly, which helps stabilize the mousse without breaking down when cooled.
For best results, mix arrowroot powder with a small amount of cold liquid before incorporating it into the mousse mixture to avoid clumping. Avoid overheating as arrowroot can break down and lose thickening power if boiled excessively.
Compared to cornstarch, arrowroot yields a slightly clearer and silkier mousse, preserving the delicate texture and enhancing the glossy appearance, making it ideal for chocolate mousse.