Preheat the oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.

In a mixing bowl, cream together 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 the flour, baking powder, and salt. Gradually add to the creamed mixture alternately with the milk, starting and ending with the flour mixture.

Gently fold in the blueberries.

Pour the batter into the prepared cake pan and smooth the top.

Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.

Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.