Combine all of the ingredients into a medium saucepan over medium low heat.
Cook while stirring occasionally, until the berries reach a low boil.
Turn the heat to a simmer and allow to cook another 10 minutes, or until all of the blueberries have burst.
Make sure to stir every so often to prevent burning.
Allow to cool before serving.
Notes
This sauce is delicious on yogurt, ice cream, and even as a topping on buttered toast. I store it in a tightly covered container in the fridge for about a week... if it lasts that long!