Preheat the oven to 425 degrees F. Grease the bottoms of a 12-cup muffin tin, or line with paper cups. Set aside.
Whisk together the all-purpose flour and the whole wheat flour, sugar, baking powder, cinnamon, and salt. Make a well in the center and add the milk, oil, and beaten eggs. Stir until just combined, then fold in the blueberries.
Divide batter evenly among the muffin tins, I like to use a cookie scoop. Sprinkle with brown sugar if desired. Bake for 5 minutes at 425 degrees then reduce the oven temperature to 350 degrees and bake for an additional 14 to 16 minutes, or until golden brown. Immediately remove muffins from the pan to cool.
Notes
For longer storage, they keep in the freezer for up to 3 months for best flavor.