Preheat your waffle iron according to the manufacturer's instructions.
In a large bowl, whisk together the flour, baking powder, salt, and sugar.
In a separate bowl, whisk together the eggs, milk, melted butter, and vanilla extract.
Pour the wet ingredients into the dry ingredients and gently stir until just combined. Do not overmix.
Fold in the blueberries.
Pour the batter onto the preheated waffle iron and cook according to the manufacturer's instructions until golden brown and crispy.
Serve immediately with your favorite toppings, such as maple syrup, whipped cream, or more fresh blueberries.
Notes
For extra fluffy waffles, separate the eggs and beat the egg whites until stiff peaks form. Gently fold the egg whites into the batter just before cooking.