Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.
In a large mixing bowl, combine flour, sugar, baking powder, baking soda, and salt.
In another bowl, mix melted butter, eggs, vanilla extract, and buttermilk.
Pour the wet ingredients into the dry ingredients and mix until just combined.
Gently fold in the fresh raspberries, being careful not to overmix.
Evenly distribute the batter into the prepared muffin tin.
Bake in the preheated oven for 18-20 minutes, or until a toothpick comes out clean.
Allow muffins to cool in the tin for 5 minutes before transferring to a wire rack.
Enjoy warm or at room temperature, as desired.
Store any leftovers in an airtight container at room temperature.