Chile-Ginger-Mint Jellies

Bring 2 1/2 cups water, ginger, sugar, and chiles to a boil in a 2-quart saucepan, stirring until sugar is dissolved. Reduce heat and briskly simmer for 10 minutes. Stir in mint, then remove pan from heat. Cover pan with a lid and let stand for 15 minutes. Strain ginger-mint tea through a fine-mesh sieve into a large liquid measuring cup or bowl. Sprinkle gelatin over remaining 1/2 cup water in cleaned saucepan and let stand for 1 minute to soften. Heat mixture over medium heat, stirring, until gelatin is dissolved, then stir mixture into ginger-mint tea until combined well. Measure liquid, and if it's less than 2 1/2 cups, add more water. If it's more, don't worry. Let mixture cool for 30 minutes, then divide among six (6- to 8-ounce) serving glasses. Chill jellies in a small baking pan, tops of glasses covered with a sheet of paper towel secured by plastic wrap, until set, at least 4 hours. Beat cream with sugar in a bowl with an electric mixer until it just holds soft peaks. Top jellies with cream, candied ginger, and mint sprigs.