In a sauce pan, combine blueberries, water, and sugar. In a small bowl, combine the lemon juice and cornstarch until blended and add to the sauce pan. Stir to combine.
Bring mixture to a boil. Reduce heat to simmer and simmer for 5-10 minutes until thick. Remove from heat and set aside.
In a bowl, beat together the eggs, oil, milk, vanilla, lemon juice and sugar together.
In another bowl, whisk together the flour, cornstarch, salt, and baking powder.
Add the dry mixture to the wet mixture along with the lemon zest. Whisk together just until smooth without over mixing.
Cook in waffle maker according to manufacturer's instructions. I got 6 waffles in my machine.
Serve waffles topped with blueberry syrup and sweetened whipped cream if desired.