Whisk the butter, sugar, salt, eggs, and vanilla together in a bowl.
Sift the flour and baking powder into the butter mixture. Stir.
Add the berries to the mix and gently fold a few times.
Add the buttermilk and mix gently.
Scoop out the dought into paper-lined muffin pans. Sprinkle with additional sugar if desired, and bake for 20 to 35 minutes, depending on the size of your muffin pans. This will make 12 standard sized muffins or 6 Texas sized muffins.