Preheat. Preheat the waffle iron and spray it with non-stick cooking spray.
Mix dry ingredients. In a large mixing bowl, combine all dry ingredients (flour, sugar, salt, and baking powder) and stir until thoroughly combined.
Mix wet ingredients. Whisk together the wet ingredients (eggs, buttermilk, vegetable oil) in a separate medium bowl.
Mix the batter. Add the wet ingredients to the dry ones and mix gently until just combined. The batter may have some lumps, but there shouldn't be any dry spots.
Fold in blueberries. Gently fold in the blueberries until evenly distributed.
Cook. Scoop the batter into the hot waffle iron, about a half cup at a time, depending on the size of your iron. Cook until golden brown.
Serve. Serve with syrup and butter or with whipped cream and additional blueberries.