Make sure the baking rack you are going to use is in the centre of the oven.
Using a mixer cream together the butter and sugar.
Add in the eggs one at a time, then add the vanilla. Mix well.
In a separate bowl whisk together the flour, baking powder, baking soda and salt.
Add the dry ingredients to the butter mix, alternating with the buttermilk (with the mixer on low speed, add some flour mix, then pour some buttermilk, then add the rest of the flour mix, then the rest of the buttermilk). Mix until just combined, don’t over mix the batter..
Using a rubber spatula, gently fold the blueberries into the batter (gently so the batter doesn’t become blue). I have actually found that fresh berries work best because they don’t colour the batter.
Line a muffin pan with paper liners (cupcake liners).
Scoop the batter evenly between 12 muffin cups for 12 large muffins, or you if you want smaller muffins, spread the batter between 16 muffin cups.
Sprinkle some sugar on to the tops of the muffins (this will create a nice sugary crust).
Bake for 20-25 minutes. The muffins are done when a toothpick inserted into the centre comes out clean.
Let the muffins cool on a wire rack for at least 15 minutes before you eat them! Any sooner and the muffin will stick to the paper liner.