Pour half the orange soda, all the bluberries and swerve into a saucepan over medium flame.
Mix the xanthan gum with the other half of orange soda, raise heat to a boil, pour in the xanthan gum mixture and cook on the boil for 60 seconds while stirring.
Take the saucepan off the flame and pour in the lemon juice.
Let cool. Goes best with pancakes.