Rinse 12 ounces fresh cranberries in a colander and discard any that are mushy.
In a medium saucepan, combine cranberries, 1/2 cup orange juice, 1/2 cup brown sugar, and 1/2 cup granulated sugar.
Cover the saucepan with a lid and cook over medium heat until the mixture comes to a boil and cranberries begin to pop, about 5 minutes.
Remove the membrane and seeds from 1 jalapeno and slice. Add the jalapeno slices to the cranberry mixture, replace the lid, and let sit for 2 minutes.
Pour the mixture into a blender or food processor and puree until smooth.
Transfer to a gravy boat or serving dish. Let the sauce cool slightly before serving. Serve warm for a pourable sauce, or chill completely for a gel-like consistency.