How to Make It
Stir together piloncillo, blackberries, and 1/3 cup water in a medium saucepan. Bring to a boil over medium-high. Boil, stirring occasionally and mashing blackberries with the back of a spoon, until piloncillo is dissolved and mixture has thickened slightly, about 15 minutes. Add cardamom pods, cloves, and salt; reduce heat to medium, and simmer 1 minute. Remove from heat, and let steep 15 minutes. Pour mixture through a fine wire-mesh strainer into a bowl; discard solids.
Piloncillo is raw cane sugar that can be purchased online or at a Mexican market. Use a box grater to grate the hard cone-shaped sugar, or place it in a plastic bag and smash with a meat mallet.