Add the water, orange zest and swerve to a saucepan and bring to a simmer. Add in the cranberries and lemon juice, then simmer on low for 12-15 minutes or until the cranberries burst open. Be sure to stir occasionally.
If you want your sauce a little more chunky, cook closer to 12 minutes, if you want a smoother sauce, cook closer to 15 minutes. The longer it cooks, the more the cranberries will break down. Mine took exactly 14 minutes, which was perfect for me.
Remove from the stovetop, transfer the sauce to a bowl, cover and chill in the fridge until you are ready to serve. Store leftovers in an airtight jar for 5-6 days.