Step 1

Combine blackberries, maple syrup, water, lemon zest, lemon juice, cardamom and salt in a medium saucepan over medium heat. Cook, stirring occasionally, until the blackberries begin to break down and the mixture thickens slightly, about 20 minutes.

Step 2

Serve warm or let cool completely before transferring to an airtight container; refrigerate for up to 2 weeks or freeze for up to 3 months.