Preheat oven to 350 degrees and lightly grease a 9 in baking loaf pan.
On low speed in a mixing bowl, cream the butter.
Slowly add the sugar and mix until it is "fluffy."
Add the vanilla then add one egg at a time.
In a separate bowl, whisk together the flour and baking powder (this is the dry mix) and set aside.
Mix the milk and buttermilk together and set aside.
Add 1/3 cup of the dry mix and 1/4 cup of the milk mix to the batter. Once mixed, add another 1/3 cup and 1/4 cup. Continue until all mixed in.
Set aside 1/2 cup of the blueberries.
Pour 1 cup of the blueberries into the batter. Carefully stir by hand.
Pour the batter into the baking loaf pan.
Carefully sprinkle the rest of the blueberries on top of the batter and with a spoon or your hand, lightly push them down into the batter. Most will still be poking out - that's okay! They will sink still.
Sprinkle the sugar across the top.
Bake for about 60 - 65 minutes. Top should be brown.
Check if the middle is baked. If not, then cover in foil and bake an additional 8 minutes and check it.
Bread is done when a knife inserted in the middle comes out "almost" clean.
Let cool for 15 minutes before serving or removing from the pan.