Cook the butter in a saucepan on medium-low heat, stirring occasionally until it becomes fully brown which should take 5 minutes. Add in the swerve, heavy cream and salt. Then add in all the rest of the ingredients. Keep stirring until it is all fully mixed.
Keep cooking on low for 15 minutes without stirring at all. If it's too thick add some more heavy cream. Refrigerate for a few days. You could heat it up before serving or serve the way it is.