Start by preheating the oven to 400F. Line a muffin tray cavitied with 11 liners.
Toss the blueberries with the ½ tablespoon of flour to coat them, and set aside.
Combine in a medium bowl, the flour, cornmeal, baking powder and baking soda. Mix to combine.
In a separate, larger bowl, whisk together the melted butter and brown sugar. Add in the egg and whisk until the mixture starts to thicken. Whisk in the milk until smooth.
Stir the dry ingredients into the wet ingredients until the batter comes together, without overmixing.
Fold the floured blueberries into the cornbread batter. Let the batter rest for 2-3 minutes as you prepare the muffin tin.
Line 11 muffin cavities with liners and divide the batter in between them.
Place the muffins in the preheated oven and bake for 23 minutes, or until a toothpick inserted in the centre comes out clean.
Remove the baked muffins from the pan and place on a cooling rack to cool completely.