Preheat waffle iron according to directions.
Mix flour, baking powder, salt and sugar in mixing bowl. Set aside.
Mix egg, milk, lemon juice and oil in small bowl.
Add to dry ingredients and stir.
Stir in yogurt and blueberries.
Rest for 10 minutes.
Spray the iron with non-stick cooking spray, then pour the amount of batter recommended by the manufacturer onto the center of the iron.
Close the lid of the iron and bake for 3-5 minutes or until the waffle is golden brown.
Serve warm and ENJOY!