Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.
In a mixing bowl, cream the softened butter and sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract.
In another bowl, combine flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with milk.
Gently fold in the fresh blueberries.
Pour the batter into the prepared cake pan.
Bake for 40 minutes or until a toothpick comes out clean.
Allow the cake to cool before dusting with powdered sugar and serving.