Preheat oven to 375°F and grease a 12-count muffin tin.
In the bowl of a stand mixer, combine the flour, baking powder, baking soda and salt.
In a separate bowl, combine the butter, oil, sugar, eggs, sour cream and milk.
Pour the wet ingredients into the dry ingredients and mix on low until just combined.
Use a rubber spatula to gently fold in the blueberries.
Scoop the batter into the muffin cups, filling each cup to the top.
Sprinkle generously with coarse sugar.
Bake 20 minutes or until golden brown and set in the center of the muffin.
Let cool for 5 minutes, run a butter knife around each muffin and remove to a wire rack.