Wash and drain blueberries.

Combine blueberries, water, and sugar in a heavy saucepan.

Bring the mixture to a boil over medium heat.

In a separate small bowl, mix cornstarch and water until smooth to create a slurry.

Gradually pour the cornstarch slurry into the boiling blueberry mixture, stirring constantly.

Continue to cook, stirring occasionally, until the sauce thickens.

Remove from heat and stir in lemon juice.

Serve warm or cold over pancakes, ice cream, or other desserts.