Preheat your oven to 350°F (175°C) to ensure even baking.
Grease your muffin tin with cooking spray or line with paper liners.
In a large mixing bowl, whisk together the flour, baking powder, sugar, and salt.
In another bowl, whisk together the buttermilk, eggs, vanilla extract, and melted butter until smooth.
Pour the wet ingredients into the dry ingredients. Gently stir until just combined.
Using a rubber spatula, gently fold in the blueberries.
Scoop the batter into the muffin tin, filling each cup about two-thirds full.
Bake for 18-20 minutes, until golden brown and a toothpick comes out clean.
Cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.