Sweet-and-Tart Cranberry Ginger Jelly

Put cranberries, sugar, ginger, and 2 cups water into a medium saucepan. Cover, and bring to a simmer; cook, stirring occasionally, until berries are soft, about 10 minutes. Pour through a sieve into a medium bowl; discard solids.

Meanwhile, put 1/2 cup cold water into a bowl; sprinkle with gelatin. Let soften 5 minutes. Add cranberry mixture; stir until gelatin has dissolved. Refrigerate, covered, at least 4 hours (up to 1 week).