Rinse the blueberries under cold water and remove any stems.

In a saucepan, combine the blueberries, sugar, and water.

Bring the mixture to a boil over medium heat, stirring occasionally.

Once boiling, reduce the heat and let it simmer for about 10 minutes, or until the blueberries burst and the mixture thickens.

Stir in the lemon juice and vanilla extract, then remove from heat.

For a smoother syrup, strain the mixture through a fine mesh sieve to remove the solids.

Let it cool before transferring to a bottle or jar.