In a large bowl, whisk together the flour, baking powder, baking soda, salt, and sugar.
In a medium bowl, whisk together the butter, eggs, vanilla extract, sour cream, and milk until smooth. Pour the mixture all at once into the flour mixture and stir until just incorporated. Stir in the blueberries. Try not to overmix the batter; if a few lumps remain, that is fine.
Dollop 1/4-cup portions of batter onto the hot waffle iron. Cook until golden brown according to your waffle iron's instructions. Transfer to a wire cooling rack while you make the glaze.
In a small bowl, whisk together the confectioners' sugar, butter, maple syrup, and milk. Whisk until smooth.
Drizzle the waffles with the maple glaze and top with additional blueberries. Serve.
Note-the waffles freeze well. Cool completely and place in a freezer bag for up to one month. To reheat, place in the toaster or microwave.