2 cups (1 pint) fresh blueberries
1/2 cup sugar
1 cup water
1 teaspoon lemon juice
Stir first 3 ingredients in a pan over medium-high heat until sugar dissolves. Bring to a boil, stirring occasionally, until berries have burst, about 5 minutes.
Mix in lemon juice. Cool to room temperature, then pour into molds and freeze.