1. Cook cream and ginger in a heavy nonaluminum saucepan over medium-high heat, stirring often, 3 to 5 minutes or just until bubbles appear (do not boil); remove from heat, and let cool completely (about 20 minutes). Chill 4 to 12 hours. (Cream needs to be ice-cold before beating.)
2. Pour cream mixture through a fine wire-mesh strainer into a bowl, discarding ginger. Beat at medium-high speed with an electric mixer 1 minute or until foamy; increase speed to high, and gradually add powdered sugar, beating 2 to 3 minutes or just until stiff peaks form. (Do not overbeat or cream will become grainy.) Use immediately.