Add all ingredients, except vanilla extract to a small sauce pan. Lightly crush blueberries with a potato masher or back of a spoon.
Place over medium-high heat. Bring to a boil, then reduce heat to a simmer. Simmer for 15 minutes, stirring occassionally.
Using an immersion blender* blend the sauce for 30 to 60 seconds
Strain the sauce through a fine-mesh sieve, push the blueberries to extract as much juice as possible. Stir in vanilla extract. Serve warm or at room tempature.
Video
Notes
*You can also serve the syrup with the chunks or use a regular blender to puree.
Syrup can be stored for up to 2 months in the refrigerator.