In a small bowl, whisk together the 1/4 cup water and cornstarch. Set aside.
In a saucepan, combine the blueberries, 1/2 cup water, orange juice and sugar. Bring to a boil, stirring occasionally. Add the water-cornstarch mixture to the saucepan, reduce heat to medium-low heat and simmer for 5 minutes or until desired consistency has been reached.
Remove the pan from the heat, stir in the vanilla and pour over waffles or pancakes. If using later, let the sauce cool and store in a sealed container in the fridge until ready to use. Before use, reheat in a saucepan or in the microwave!