Preheat your oven to 200 degrees and lightly grease two 12 hole muffin baking trays.
Place the butter into a microwave safe bowl and cook for 30 seconds or until melted. Set aside to cool.
In a large mixing bowl, sift the flour and add the sugar before stirring to combine and make a well in the centre.
In a large jug, combine the milk, eggs and vanilla essence.
Pour the mixture from the jug into the well and add the cooled melted butter. Gently fold the ingredients together with a large metal spoon until the mixture is almost combined.
Add the blueberries and gently fold through - make sure you don’t over mix as they blueberries will bleed (if using frozen) and overworking the mixture will give you a dense muffin.
Spoon the mixture into the prepared muffin tins and place into the oven to bake for 18 minutes or until cooked through when tested.