Add blueberries, lemon juice and water to a small saucepan and turn heat to medium-low.
Stir occasionally until mixture starts to boil. This takes approximately 8-10 minutes.
Add in allulose and stir. Reduce heat to a low simmer and cook for another 5-10 minutes. Your blueberries should start to pop and release their juices.
Stir in xanthan gum and mix evenly.
Remove from heat and let set for 10 minutes.
Serve immediately or let cool completely before storing in the refrigerator for up to 1 week.