Combine blueberries, 3/4 cup water and sugar in a medium saucepan and bring to a boil. Boil 10 minutes.
Mix cornstarch with 2 tablespoons water and add to blueberry mixture, stirring constantly until syrup is thick.
If you want a smooth syrup, pour mixture into a blender and blend until smooth.
Taste syrup, and if needed, return to saucepan and reduce until flavor is of desired strength.
Remove to a bowl and cool. Add lemon juice and stir to combine.
Serve over pancakes or ice cream.