Take butter from the fridge to allow it to soften. Preheat oven to 375 degrees and lightly grease a baking sheet with cooking spray.

Mix flour, baking powder and salt in a mixing bowl; set aside.

In a separate bowl, cream together softened butter, and sugar; add buttermilk, egg and vanilla; mix thoroughly.  Add the flour mixture, and blend.  Fold in the berries without over-mixing.

Using a large zip lock bag, place the batter into the bag, cut an opening in one of the corners of the bag, or simply use a large pastry bag.  Gently squeeze the batter out onto a baking sheet into a circle-like donut.  

Bake for 12-15 minutes, until golden brown.  Allow to cool before serving.