Combine corn starch, sugar and orange juice in 2-quart saucepan. Add 2 cups of blueberries.
Bring to a boil over medium-high heat, stirring constantly; boil 1 minute. Stir in remaining 1 cup of blueberries; cook and stir 1 minute longer.
Recipe tip: Serve sauce over pound cake, ice-cream or pancakes.